A couple days in I'm starting to notice some issues. I have had a couple bugs, nothing game-breaking and no crashes to the OS like some people have reported. Just some small things like falling through the environment and spawning into invisible space on one boss fight. Mildly annoying, but rare enough not to detract too much.
I've also noticed some gameplay issues, most noticeably when playing with multiple people. Why would they ever have grab and using items be the same button? It is extremely frustrating with 4 players trying to use the blinker ball thing, but instead we keep grabbing each other because there's only one very small platform that we're all standing on. The increased layers (which I love otherwise), also makes 4-players extremely chaotic, especially on the story levels. It got to the point that I would just leave people behind because they couldn't follow what was going on, and of course LBP still has the weird camera thing where it follows only the person closest to the goal even if you have to go the other way to actually get to the goal. I've also had a couple issues with sticky layers where it seemed impossible to jump one layer ahead, I've been frustrated with this in the past games but never quite this bad.
Edit: Another issue with 4-player. To play online, all 4 local players need to have a PSN account. At least that's what it seemed like when trying to use guest accounts. A lot of my friends don't have PSN accounts, so this is a pretty big annoyance that they need an account just to play local co-op with me. If somebody knows a way around this, please let me know.
A couple gripes, but it's still an incredibly charming game. The story feels more like a return to LBP1's quirky story and less of LBP2's child fairytale story (which I found to be grating after a while). I think the new hub worlds really work, it makes it feel like a real world to explore and not just a series of levels. I haven't even started in Create mode, but played a couple of the top community picks and they're very good. I also really like the new create a solution levels, reminds me a lot of Scribblenauts and Nuts and Bolts, both of which I really enjoyed.
A lot of the issues listed above (all but 4-player chaos, probably) could be fixed with a patch and hopefully it does. Right now I'd give it 8/10.