>>38912777>>38912800They're all different and all good (except Digimon World 4 and Data Squad)
Digimon World 1 is fun if you want a retro PS1 game but its notoriously obtuse. If you want to relive the childhood experience of not knowing shit about the game you're playing the World is perfect for that.
Digimon World 2 is kind of like a Mystery Dungeon game mixed with SMT.
Digimon World 3 is a more traditional JRPG and probably the easiest to get into. I like it but it's not great.
You could emulate Re:Digitize for PSP with a translation patch.