As far as an editor goes, you might also want to look at Kurohyou’s work here. His editor is highly inspired by Unity, which really is a good thing. I’m also working on a SDK, but it’s not ready for prime time yet.
Regarding technical limitations, the ones I’m most concerned about are the lack of 16 or 32 bit per channel textures (not exactly a show stopper, but makes some stuff more difficult) and the lack of hardware skinning – in Panda, all animations are done on the CPU, which is a performance bottleneck.
Other than that, there aren’t any real technical limitations, but there is a lot of stuff that Panda won’t do for you, while the likes of Unity would (in exchange for $1500 
). For instance, Panda’s OOTB light support is very basic, so you will need to figure out a way to manage lights. If you want deferred shading, you gonna have to roll that out yourself (although the snippets section will be of great help, IIRC). Panda has portal culling, which is essential for many kinds of games, but it won’t create portals and cells for you (which also means you can set them up by hand in the most optimal configuration). And, as Nemesis mentioned, Panda doesn’t have a “tried and true” design pattern for your game and assets, and that also includes the lack of a map format.
All this isn’t really a bad thing, it just depends on what you expect and need. While doing all this stuff is certainly not faster than having an engine that does it for you, it’s a lot more flexible and you get a lot more control in exchange. You will also find that Panda is great at not getting in your way, so there’s nothing it can’t do, there’s just stuff it doesn’t do OOTB.
I absolutely agree. The snippets section is awesome, but some really useful stuff might get lost in it. Something more structured would be welcomed, but I would personally prefer tags over sections. Some snippets are almost entire libraries, in fact, so it might be very difficult to figure out where they belong.
PS.
Actually, it’s “guy” that made LOVE, not “guys”. That whole thing is one man’s work. Which kind of proves anything’s possible ;D.