From the looks of it, it's a fairly decent middleman service. It's traded in yen which is in American buyer's favor right now. With it being 250 yen + 10% right now just to place an order, not quite competitive enough with SMJ's at $4 flat rate. Will likely be very close to other proxy services. My guess is SMJ will still win over this option. CDJ does seem to look frendlier. Let's see if they select retailers or let you select even if it might have a competition angle (like Tower Record Japan, who produces many exclusive remastered/reissues).
My issues with CD Japan are they've been known to take a week just to process an order on their site whereas Amazon JP gets it done in a day or two with less costly and very effecient DHL as opposed to FedEx (very fast, more expensive) and EMS (which means you have to deal with the US post and their byzantine policy of not allowing signature release).
What always prevents me from using them and other proxy services is the variable "procurement fee" (acquiring the item inside Japan, shipped to the proxy buyer address) which can easily make the final total almost 2.5x the cost. For me, it's the nuclear option and it's gotta be something that has a once-a-year auction frequency.