Technically the first two are DWM (Dragon Warrior Monsters) as they existed before the stupid name change.
It is a great game if you aren't the type to shout "Pokemon Clone!" at any monster catching game. The breeding system for the 2nd one (can't remember if the first had it) is so much better then Pokemon's. The leveling also make more sense. I forgot the exact numbers but you can't expect a slime to be trainable to the level cap, it be more like around lv20-30. So it encouraged catching. With that said though either the first or 2nd, forgot which go CRAZY with giving freebies. So it be like getting Zapdos, Mewtwo, Mew, etc just for playing the game.
As for the DS game I can't say anything about that. As far as I could know they completely changed the system. I only speak for the first two.