Yeah, the tech preview is so limited you aren't missing much.
If I could copy DratsaB's review technique:
Interface = ok, but I'd prefer to be able to adjust everything whilst on track, like in LFS.
Sound = good, much better than nKpro
Physics = very low speed weirdness (suspension stops working completely if you slide to a stop) and other issues aside, it's excellent.
FFB = quite good overall but simply not as intuitive as LFS imho. LFS might not have the most realistic tyres or physics, but I still feel completely connected to them.
FPS= only a 7770 and I'm surprised how well it works, BUT, if I average 90fps on my own, how am I going to do with ten other cars kicking up dust and smoke? Not a big issue in LFS to dip to 35fps at the start of a race, because the steering always keeps up brilliantly until you get to single figures, but in Assetto Corsa, for whatever reason, there is steering lag at lower framerates. And it's going to be an issue, I'm sure.