You're not going to find super-impressive Snapmaps yet. Or all that often.
It's really a lot like how it is in LittleBigPlanet; the engine is capable of doing amazing things, but few levels actually DO those amazing things because they require learning the logic circuits, and also require that you be good at using them. Many users will opt for the lazy route every time; just stamping some things in, drop some monsters, maybe use extremely basic logic setups, and that's about it. It's how it always goes for this sort of thing.
Same thing with rooms.... I've seen few maps using objects in creative ways to reshape rooms & hallways to fit different ideas. *I* am doing it, but I've only seen like, TWO maps so far that also do it. It's not like it's HARD, but again, there's effort involved, so people wont do it often.
There hasn't been enough time yet for really amazing things to come out, either. Those can take a LONG time to put together; I tend to do this sort of thing pretty fast myself, but it usually takes a good couple of weeks to do a major one. Either way, after a few weeks, some may start to show up.
Also there's a couple of rather unpleasant bugs in it right now. Certain types of logic can abruptly break through no mistake of the designer.
As for the MP, I haven't touched it since release, myself. I may or may not get back to it at some point. It's fun enough but I tend not to stick with multiplayer games that aren't fighters.