I use a Mech Tech I bought a dedicated Glock lower for and it perform fantastic. Cost was low as I bought the upper used and the Glock lower was a take off I bought on Gunbroker, total in the rifle was about $500. Uses Glock 17 mags in all sizes from 17 up to the 50 round drum...I use mostly the 32 round sticks in it and the Korean cheapies work great. Mine is the fixed stock older version but the new are very flexible in stock and fore end choices.
They are a lot of fun. I love mine. I also have three friends who have them.
I saw that a few weeks back but haven't seen any reviews yet. I was hoping someone on here would get one.
We need somebody on here to pull the trigger and see how they are.
definitely will be on my b day wish list