DW3 isn't awful, and does a good job with the turn-based style of RPG fights, but the lack of any quick-travel options hurts the game badly. Not to mention it's easy to forget your next objective. I've owned the game for years, and I STILL have no clue what I'm supposed to do next.
DO NOT touch DW4. It's easily one of the worst games I've played. It tried to hook people with the X-Men Legends style of gameplay (4P co-op, leveling and equips, etc.), but it failed miserably in the execution. I couldn't get rid of the game fast enough.
The DS games are fantastic. They have a system in place similar to Pokemon's EVs, but it's even less required and much easier than Pokemon. The battles look really simplistic with barely any animations, but it's not a huge deal. Digivolving is also different from the other games. Each Digimon has a level cap that can only be raised by digivolving up or down a level. DW4 tried this system, but the game botched it by having your stats reset to 1 each time. In the DS games your stats don't reset, but they rise/fall accordingly. You can eventually max out your stats by constantly digivolving, and by putting them into your "farms" (which is the equivalent of Pokemon's PCs) where they can do individual training and raise certain stats and elements. It's very, very in-depth and also surprisingly simple.
Digimon World Championship plays kinda like Pokemon Ranger, where you control everything with the stylus, but the battles themselves are random in the sense that you only control where your team moves. You have to hope that they use the moves you have assigned them. A friend of mine who loved World DS and Dawn/Dusk didn't like Championship at all.
