As far as reviews go, if I were reviewing this game, I'd probably give it somewhere in the 7/7.5 range. And honestly, that's probably being relatively generous just because I'm a Falcom fan.
As far as gameplay goes, the game nearly IS a Lunar title. I'd venture to guess that it's far more spiritually similar to Lunar 1 and 2 than the actual Lunar game for the DS ended up being. This isn't necessarily that bad of a thing, but I always found the Lunar games to be fairly generic games that were saved by charming translations done by Working Designs. Legend of Heroes IV's translation is anything but charming.
It's the thing that you've probably heard the most about, and everything is probably true. This has, hands down, the worst translation job I have EVER seen in a video game. Mind you, the dialogue isn't incomprehensible... it's merely grammatically pathetic. There was never a moment where I didn't understand the meaning of something, but there were plenty where I desperately hoped the translators were not native English speakers. Hell, I hope they weren't even English trained Japanese people. The English teachers over here with the worst English ability I've worked with wouldn't make half the mistakes that were made in this train wreck of a localization. I think it's entirely possible large sections of text were simply babelfished.
ANYWAY, I really don't want to harp too much on the translation because plenty of other people already have. Instead, next I'll complain about the gameplay! I think I stated earlier that this feels like a well-made Falcom game that was butchered by Bandai. Honestly, no RPG should ever have control issues like this does. Even using the d-pad, Avin's actions in the field seem completely random. I never knew where he would run off to next if I accidentally walked into a wall (where instead of stopping, he'll keep running full speed in a different direction!). Even more annoying, I could never tell where I could and couldn't go in towns. There are places where you can run up on top of walls and places you can fall down and places where you can't and there is NO rhyme or reason to where you're allowed to go and where you aren't.
Thankfully combat isn't quite as much of a chore. The thing I found most irritating is the fact that the PSP's screen orientation actually seems to affect combat strategy. If you run into enemies from the top or bottom, your characters show up at the bottom of the screen and the enemies are at the top. If you run into them from left or right, the combat has you on the right and enemies at the left. For the latter, the screen orientation is so wide that half of your characters can't actually reach the enemies in the first round of combat. Thankfully, running from battle seems to have a 100% success rate, so I just always did that and then reengaged in battle to get the other orientation for the sprites. The other slightly annoying thing in battle was the fact that the PSP noticably had to spend time loading even the simplest of spell effects. Then again, that does give you more time to read the completely nonsensical babbling of your characters while they're casting, I guess...
My thoughts are definitely not entirely negative, though. I think mostly I just wanted to start with the bad stuff because I now can honestly agree with the complaints most reviewers had of the game.
The best part is definitely the story and the characters. Despite the appalling translation, the character interactions shone through as some of the most touching relationships I've encountered in an RPG. To answer McCall's question, yes, Mile (that is his English spelling) did totally seem to have a crush on Avin throughout... apparently that's not something that simply showed up due to the bad translation. In fact, to be completely honest Mile/Avin felt written far more like a romantic relationship and Avin/Rutice was much more like a good friendship. The latter I assume is a victim of the translation, since I didn't really see it coming when they got together at the end. Shannon was annoying to the extreme, but still, Mile's reactions to her were quite entertaining.
Of the other characters, I LOVED Muse... I wish she'd spent more time in my party. I also enjoyed the progression of Martie from adventurer to full-fledged member of the castle guard. Douglas and Lucias made a fantastic pair... I thought they were really well done. Gawaine surprised me because he seemed to be the sort of character who'd never be in my party, or even if he was, he'd be overly powerful and then get killed off in the plot. I was really happy to see him survive and see my characters build themselves up to his level. I never would've guessed he would be part of my party in the final dungeon/battle.
I'm extremely curious to know how the rest of the Gagharv trilogy fits in with this one. It seemed fairly obvious that Michel was going to go off and give the Bardus sword to one or both of the heroes from the other games. Presumably Jurio, since I think Michel's homeland is the world from that game in the series.
I wish that the series had a better chance of coming to the states in its entirety, but I'm guessing the hack job that was this game's localization probably turned off a LOT of people (especially reviewers and the people who read them) and this in turn led to rather poor sales. I wonder if there's any chance whatsoever that Bandai would bring over Cagesong of the Ocean or The White Witch. This seems extremely unlikely, especially since the White Witch bonus stuff was cut out of the US version of IV, plus there's no clear data save option either. I'd really like for it to happen, though, and I'd even suffer through a translation as terrible as this just to get to play them. Time will tell, I guess... but I'm not gonna hold my breath.
 one final note: was I the only one who was shocked that Madram WASN'T Avin and Eimelle's father?