Hotz has described his product as 'fancy cruise control', and it isn't much more than that. I think he's about as legit as he says he is.
If he gets it out for under $1000 before 2017 he's a man of his word, and I think he'll do it.
After pulling off that impressive stunt, though, he's going to have to figure out how to turn comma.ai into a real company somehow. I'm not sure how he's going to do that.