Super Paper Mario was a great game, I just prefer the first 2 games for requiring more strategy and having you to think a little more. For example, you can pretty much just get away with KOing the enemies using Cudge or Boomer, and then using Peach's Umbrella Shield when necessary (which is why she was my most used character). Meanwhile in the first 2 games, you have to think on what Mario will do and what your partner will do, you need to setup your badges, use your items and change partners smartly, know how to (Super) Guard and do Action Commands successfully, etc.
It still felt Paper Mario-esque though, unlike Sticker Star. I would much rather have Super Paper Mario over Sticker Star any day.
The story wasn't bad, and some soundtracks are pretty cool (I always loved Soft Light and Proof of Existence), but I still find TTYD has the best soundtrack. =P