I don’t like how it doesn’t appear to be as customizable as the AR-15. The entire lower is molded, so you can forget about changing out the grip or trigger guard. The stock can be changed, but it appears complicated, which will no doubt add to the cost of any aftermarket versions that will come out.
Looks like with this gun you can forget the days of buying a stripped upper, lower, barrel, parts kit etc.. and assembling your own.
I still am not quite sold on the whole piston driven system either.
Check out TheFirearmBlog for the whole set.