first they both make great products
but what might drive you to pick is who can give you the rig you want
also look at the magazine issue, call them and ask what type works and what doesn't
there are a lot of folks waiting in line for these rifles, i one of them
the mag issue isn't going to bother me, i plan on having 2-4 total
but some want 20-100 mags for what ever reason
if you want more info go to ar5.com
loads of info on the ar10 platform