I'm a Magpul fan. I think their products are very innovative.
I like the BAD lever, and have it installed on two of my ARs. I love the fact that I can (now) lock back the BCG without losing my firing grip. I always hated that about the AR design, and the BAD lever solves the problem. I know many other shooters that have had the same wish, so it is definitely a great solution to the problem. My trigger finger never goes inside the trigger guard while using it, so I feel completely safe using it. I love the MOE grip, and it is an addition to all of my ARs. I prefer it's shape and grip texture over the MIAD grip. The MOE stock is nice, but I prefer the CTR stock due to the fact that it has a QD sling attachment point. The ACS stock was a bit of a disappointment: I run Crane SOPMOD stocks on my ARs, and was pleased that the ACS stock had the same profile, but I hate the fact that it has no QD sling attachment. I don't know why they did not put one on there. It is still a nice stock, though. The UBR stock is nice, but quite heavy. I have never used the ASAP sling attachment, but the metal on metal seems like it would make too much noise.
All in all, I think Magpul makes great products.