First of all I do not buy that the Mag-Pul make them more reliable, not with GI mags in 5.56 anyway. With tens of thousands of rounds of 5.56 down range with GI mags and never a problem, how can the MP follower make it more reliable? However, you have got to love the anti-tilt feature of the follwers and I have switched all of my shooting mags over to MP followers. My C&R license lets me get them from Brownells for a measly $5.09 per 3 so WTF.
Where they really shine IMO is on the .458 SOCOM. Many times when loading the mags I have tipped the GI follower and jambed them up. Since you must slide the .458 SOCOM round in from the front, if you get in too big a hurry on the first round you will tip the green follower down, and I have done it quite a few times. The MP follower prevents that. So far I have bought about 70 MP followers and have used about 50 in replacements. They are well worth the money IMO especially if you shoot the .458 SOCOM and .500 Phantom.