Despite its relative age, Suikoden Tierkreis stands out as a top JRPG on the DS.
While that may sound like "ugh, not again", even though this is a little bit of an older title, I've played dozens of JRPGs on the DS, and this actually compares very well to even the hot new ones like Dragon Quest IX.
The good:
* Good graphics -- while not quite as big and bright as the new Dragon Quest games, it's still much better looking than some of the straight ports (looks better than Final Fantasy III, for example). It features a lot of well animated in-game animation sections (machinma) as well as a bunch of pretty nice looking fully animated anime cut scenes. Also, the 2d background artwork in areas is extremely detailed and looks great -- you'll notice small touches like sunbeams that illuminate your 3d character, etc.
* TONS of characters -- there are over 100 NPCs to recruit and swap into and out of your adventuring party
* Plot -- the main plot is nothing special, but solid, and drives you through the game. The game features a ton of different dungeons to explore, and they're all just about the perfect size so you don't get tired of wandering through gigantic mazes and backtracking through old areas. Also, the strong set of characters makes the straightforward plot more interesting overall.
* Audio -- good musical score, many dialog sections have voice overs (which are hit-and-miss, but still nice)
* Minimal grinding required -- you CAN grind if you want, but you won't be forced into walking around empty dungeons or wandering the overworld just to get in as many fights as possible. In general, the combat is pretty easy.
The not-so-good:
* Random encounters -- there are random encounters, which is fine, but like so many JRPGs, you'll be in dungeons where fights are very easy, no longer give you enough experience, but you'll still fight 10 or 12 of those battles as you work your way back out of an area. Seems like they could just not generate random battles that don't really help your experience...
* A little too easy -- I actually am OK with somewhat easy JRPGs because I'm a wuss, but this one is easy even for me, which makes boss battles and such a little tedious instead of tense and exciting, because you don't often feel like you're in danger.
Overall, if you like JRPGs and haven't played this one because it's "old", fear not -- pick it up and play!