I think its great.
"I would never pay $20 for an incomplete game."
Then don't.
I'm enjoying the Assetto Corsa early access. I suppose it helps that its a racing simulator so there's not really anything to spoil or progress to lose or anything like that. But I got this game cheaper than it would have been on release, so, I mean, I *could* just never play it until they release version 1.0 and just treat it as a pre-order that saved me money, but its been good fun with the drip feed of content and features. They update the game every other Thursday, so its always something to look forward to.
The game is shaping up great, for anybody interested. Physics are phenomenal.