so nobody use Nebula Device ?

There aren't any real tutorials, though they've finally started putting together some mini-examples that will hopefully be helpful. The few I've seen so far, though, aren't helpful - they're overly complicated and you basically just are given a bunch of code to wade through on your own.

Join the mailing list, though you won't get a lot of help there, check their IRC channel, and look through the code for nviewer and bombsquad bruce. And look through the docs, of course. All that will help a little, but really you're left just trying to figure it out on your own.

N2 is mainly a graphics engine, though they have started adding a general framework and support for things like networking. ODE works with N2, and there's a sample app with the code that shows how to use it, but I'm not sure how integrated it is...check out the code in the cvs from sourceforge and look at the "physdemo" stuff. I think Cal3D also has at least some support, but I haven't used it at all so I'm not sure...look in the docs or ask on the mailing list, someone will probably at least tell you if it supports it yet.

As for the SDK, I'm not sure - it's kind of funny because 2 separate groups are working on the engine, and then every month or two they combine all their work. So Radon Labs will release its own SDK every once in a while, but the cvs version from sourceforge typically has more features (and is publicly updated far more often, of course). I use the cvs version and not the Radon Labs SDK, so I don't know what's missing from the SDK. That said, I don't think it's going to be 'done' any time soon, there's still a ton of work to be done. I would expect that people will continue to create small, basic programs for the cvs, but I don't know how great they'll be as a 'tutorial'. You're really better off asking on the mailing list so you can get some specific answers from the devs.

From using N2, these are what I consider the biggest problems and annoyances:
-There are no tutorials
-No one wants to help you learn
-The docs are barely helpful
-OpenGL support doesn't work yet, so it's not cross-platform
-It's generally impossible to build the engine into a dll instead of statically linking
-Lots of stuff is still buggy
-The classes etc aren't very friendly for customization
-Some of the features of the engine aren't very efficient, but it's hard to avoid using them
-The build system is somewhat annoying

That said, it *is* still a work in progress, with a long way to go. If you're looking for something that's at least somewhat easy to learn and use, you might want to look for other engines until nebula is farther along.

I'm not very familiar with N1 since I haven't used it. Judging from what the devs and everyone else says though, if you're going to use either of them, you should probably just try to learn N2. It's annoying that there isn't much support for it yet, but you can learn it as you go by looking at existing programs and by just trying stuff on your own. The support for it should improve over time, and it is quite usable as an engine now.

Bear in mind that Radon may release their next update around December (which means it will be added with the cvs stuff by mid to late January), but the docs etc likely aren't going to be significantly different. I wouldn't expect any great tutorials until work on the engine is near completion.