I absolutely love Pikmin. The first game is in my all-time Top 5 of videogames, and I 100% it about once or twice year.
I've got the second one as well, and while I like some of the changes, all in all it didn't captivate me as much as the first one. I still haven't finished the final level. I guess it's more repetitive than the first one, and you constantly have to waste days in order to cultivate new purple and white Pikmins in the caves. The time limit of the first game made it (slightly) harder, but at least every day counted, making the game more of a streamlined, focused experience.