Hello! I'm Burrhead2, and I love Pikmin. I also have a YouTube channel by the same name, so check that out if you have the time.
What follows are my opinions on the various games.
Pikmin
One of the weaker games. I'll admit, the game does feel... off in places. The throwing speed of the Pikmin and the large amount of squash and stretch in some of the animations make it feel weird. But the strategic gameplay, coupled with the great level design and short overall play time make this game a blast to play! It's easy to pick up and put down, and endlessly replayable. And despite being simple, the Challenge Mode is actually pretty fun.
Pikmin 2
This is the first Pikmin game I ever played, so I'm quite nostalgic. Between this and Pikmin 3, it's hard to choose my favorite (Although, this one wins out by a small margin). I love this game simply because of the fact it has so much stuff to do! So many treasures and so many enemies! I always feel like I'm exploring something every time I play this game. That's likely because of the caves. I don't mind the caves in the game, y'know, I actually kind alike them. But in some cases, they do feel a bit "sterile" and "machine generated". They do negate most of the strategy the series is known for, which is a shame, because the main areas are really well designed. But they work and are pretty fun, so yeah. The Challenge Node is sort of a prerequisite for Mission Mode if you ask me, but you didn't. Using caves for Challenge Mode works quite well, given the explorative nature. Purple Pikmin op.
To be continued...