Where can you get a quality AR for $529.80?
I understand if you have to buy another Glock and this assembly, but if you already own a Glock(or two). You could also buy a Glock frame for $150, and the Mech-Tech for $530 = $680. Now you have a rifle to match your handgun, carry one type of ammo, and extra magazines that work in both.
There are other options out there including one I've been trying to find again, but even the Hydra from MGI http://www.mgi-military.com/index.php?id=27&sub_id=17 allows for Glock mags but also other conversions which are cool. I saved up for a year for my Kriss. I like the idea of having two seperate weapons using the same ammo and mags.