Level design was great I struggle to play hand held games because I don't like taking my Vita out.
I did find the level design as great as any other LBP game and the minigames are amusing. I'll obviously play the whole game through with you if you want.
Just ask yourself if you want another LBP game, I'm pretty certain in this one multiple playthroughs are encouraged as i'm missing loads of stuff and i only played most levels once. My only gripe was when i played this game most of the people i played with were really crap at this. Hopefully there should be a load of levels by now and i'm not taking this off my vita card so like i said i'd play with you. I would say though there's no real point in rushing out to get it if you aren't going to play it.
The levels seemed a lot bigger then the ones in 1 and 2, I don't know if thats a good thing to you and it did strike me as odd because normally handheld games focus on more concise chapters. Can't remember the boss fights at all.
If you want me to answer specific questions let me know, i can just check it anytime i.e. if you want to know the level themes and number of stages.