Picked up the game today, and have so far completed World 1 with all the optional Star Coins.

After getting over the initial shock that this wasn't running in 60fps (the Galaxy titles spoiled me), I've learned to like the look of the game.  At the cost of a lower framerate, there's better shading effects. (The Thwomps have never looked better!)  The 3D is very tastefully done, not at all intrusive (this might be the first 3DS game where I have the slider set to max), and yes, it really does help in gauging certain jumps more accurately.  There's a real thrill in leaping from dozens of feet in the air, and hitting your enemy's head from way up high -- almost a Jumping Flash kind of airtime rush. :)  Framerate remains the same whether you have the 3D on or not, so I have no qualms with just leaving it on.

It's refreshing to play a new Mario game that doesn't bludgeon you with countless tutorials.  In fact, there's practically none at all: you're pretty much left to your own devices on how to do everything.  Luckily, if you're any kind of Super Mario vet, you'll be able to figure it all out in a heartbeat.  (But here's one tip that may save you from a preemptive death: the Tanooki suit now floats by HOLDING DOWN the jump button, not mashing on it a la SMB3.)

Challenge wise, it's been an easy affair, but the level designs are incredibly enjoyable. The direct paths to the goals are linear, but the game's chock full of deviating paths that are always guaranteed to reward you for your curious diligence.  Be it a Star Coin, a power-up, or a 1up, there's nooks and crannies EVERYWHERE -- and I found myself playing each level in the first world at least two or three times just to find them all.

Unlike the two New Super Mario Bros. titles, the game thankfully has a Save Anywhere feature.  It also auto saves after every level.

Flaws?  You'll still amass an absurd number of extra lives in a short period of time.  At last count, I had 42 lives from the start of World 2.  Also, the new castle theme is disappointingly lackluster, especially when compared to the awesome ones featured in the two NSMBs.

Could you describe what you think about the new additions in this game? (Mario's movelist, Tanooki suit in 3D compared to wingcap, 3DS nub controls versus analog, etc.)

My biggest irritation is the lack of analog speed control.  I feel like it's super awkward holding down the Y button when I could just adjust how much I'm pushing the stick.  I get that they're trying to make it feel more like the 2D games, but that just seems silly to me.

Mario's overall movement is quite a bit slower than the Galaxy titles.  This does work in the game's favor, because the playing field isn't nearly as large, circular, or free roaming as Galaxy's.  I have no complaints about the nub.  True, you do still need to hold down an accompanying button to make him sprint full on, but there are still two varying degrees of movement on the nub alone: tilting it slightly makes Mario walk, tilting it all the way makes him trot.

Most of the rest of his Galaxy techniques carry over, including wall jumping, and the quick backwards turn super leap -- though I haven't had much use for them yet.  Triple jumping while in a sprint has been omitted in favor of a SMB2/Doki Doki Panic-esque "squat for a few seconds to charge up" super leap.

And you don't actually fly with the Tanooki suit this time -- at least, not from what I've seen so far -- only float during a descent.  It's akin to the way the Propeller suit from NSMB Wii felt.

Already finished the JP version and I'm now trying to wrap up the extra's. The game has some nice tricks up its sleeves near the end.

It's an excellent little game, that seems to love its 2D roots (SMB3 most obviously) even more than other games in the series. It starts off almost debilitatingly easy, but the end-game challenges can be extremely frantic.

I also like the street pass functions for this game. Getting items and Star Coins is very much going to help near the end, and the added Time Attack feature that allows you to compare your times against the fastest person you've run into is much appreciated.
A shame it makes no use of those walking coins, though.

Fans of the Galaxy series will feel right at home, I should think.

His movelist hasn't changed much. As Angie said, the Tanooki Suit allows you to float while holding down the jump button, and the Special Tanooki Suit lets you turn into a statue while jumping by pressing the R button (for a hip drop), but the rest is the same.
You still get the long jump by running -> crouching -> jumping, but if feels less effective for some reason, and you also still get the cartwheel jump by quickly doing a 180 degree turn, which I still find annoying because it never works when I want it to, but always when it's most inconvenient.
The wall jump is back too, so really nothing has changed much.

Also, you can't actually fly with the Tanooki suit like you could in SMB3, so comparing it to the wingcap seems pointless.

As for your 3rd question, I don't know what the difference is between nub controls and analog.
A quick google search resulted in the term "analog nub" for the 3DS so you might be confusing some terminology here.

Ah, I'd forgotten about that one!  It's definitely a little more difficult to pull off, now that you have to hold the run button as well.  Less effective, maybe, because the trajectory of the jump seems less far reaching?

And there's a new technique I believe is exclusive to 3D Land.  Holding down crouch and pressing the run button makes Mario do a forward roll.  It doesn't damage an enemy, but it does break those cardboard cut-outs when a Tanooki suit isn't handy.  (Performing the same move with the Tanooki suit results in a faster tail smack attack.)

Yeah, it definitely seems to fall a bit short in terms of far-reachingness.
Still, it was rare for me to actually feel the need to use this move in the first place, so I guess that's okay.

Oh and I totally forgot about that roll move!
Handy for quickly moving through tight spaces, but that's about the extent of it.

He means the difference in analog sensitivity between the way SM3DL controls on 3DS and the way the other 3D Mario games control on home consoles with a proper analog stick.  I believe Angie already addressed this in one of her posts.

Eh, well if it saves after every level, then lives really shouldn't matter all that much? Unless something else is lost when losing the game. Still, I never got too far into NSMB DS because of the lack of both easy saving and no easy way to get a lot of lives...not to mention, unless I missed it, no way to quick save, which is so dearly needed on a portable.

You'll be happy (or not) to know that this is the first Mario game (as far as I can recall) that doesn't cap off your number of lives at 99. I currently have 315 or so, and still going

Or, in other words, I really wish Nintendo would let go of this outdated lives system, because it's totally pointless.

No, that's good!  Now collecting lives is a feasible side quest.  I'm sure I'll be hitting 1,110 in no time.

I finally had time to sit down with this and after feeling initially underwhelmed, I'm now having quite a good time.  The game is very fun, and it really does feel like a unique mixture of the 2D and 3D Marios.  Levels are laid out with tons of little secrets and the game almost constantly rewards you for exploring and trying random things.  Completing the early levels is easy.  Getting all of the Star Coins is not.  If Nintendo had waited to launch the 3DS until this was ready, the face losing giant price cut could have been avoided, and people would have had a great proof of concept for why the 3D part of the 3DS is cool.

I'm five worlds in now and... where are the world themes?! It's a random collection of levels and there seems to be no reason whatsoever for dividing it up into worlds. That's a pretty big disappointment as I love to have coherence across the levels. Especially as, when I did world one, it gave me a shot of a lovely night time location and I thought, ooh, a night theme! But no, that was just the little letter cut scene.

Letting go of my theme disappointment, I love this. The short levels work really well and they're nicely constructed. The simple look, while edging towards bland at times, actually is mostly pretty charming. Some of the textures are lovely and a few of the individual levels look gorgeous. And the fan service in place is excellent.

Yes, the game is really easy. At the start, I felt it was more like going for a walk than playing a game but that didn't last long. I have missed a bunch of coins so there is still more challege there. Even though I say it's easy, I have died a bunch of times but mostly due to having difficulty getting to grips with the controls - an odd thing for a Mario game but with the buttons being so close on the 3DS, I find myself wishing that I could map run and jump to the bottom and right button respectively. I have missed the jump button a bunch of times because I can't just slide my thumb over and back. And the other part of that is that there are a bunch of moves carried over from 3D Marios that this one doesn't seem to need. Yet the moves are there so, every now and again, I'll do a big cartwheel jump when I didn't intend to and I'll drop off a ledge. So I wish the controls were mappable and simpler. That's just a personal issue.

Overall though, those issues really fall away because I find the game a huge amount of fun. It has some lovely little bite-sized levels and some really nice ideas contained within them.