Decent but could be better - Battle Arms Development AR15 Enhanced Modular Magazine Release

I like this mag release well enough. The attachment method for the extension seems nice and is suprisingly solid. Machining and finishing is impressively executed, as well. Most importantly, this actually does make releasing your mag an easier, quicker experience.

Unfortunately, this release has a ton of wiggle and play in the receiver sets I've tried it in. It's really just a nuissance, but compared to some alternatives, it's enough to make me recommend you look elsewhere. Personally, I've come to much prefer the V7 extended mag release - it's only a few dollars more, but I think it's worth it.