Review:
not for use with midcaps. doesnt feed at all. hi caps are fine but flash mags are the best. easy installation. will require some drilling out of one side to get the pin through all the way but thats easy with a powerdrill. most mags are wiggly but electrical tape will fix that. in other words worth it with hi caps. dont bother with mid.
Review:
Not for lefties, requires some modification, and not great for quick reloads. Its not bad though when you get used to it.
Review:
A great way to save a few bucks on M4 compatible Mags (especially if you still have a few laying around) if you're willing to upfront the cost for the magwell conversion. Only pro/con is the way the magazines look, which is up to your preference.