Well the Magpul enhanced follower does fit the contours of the mag - thus unlike the green and black follower it cannot nose dive and jam.
For must have - its really up to you. I'm a bit anal and like to try to remove the largest issues with M16FOW reliability --- the mags...
Additionally you know your mag is bent or otherwises out of spec if the follower wont run smoothly thru the range of travel.
With the CF's (Labelle Teflon) mags which are pretty much one of the best aluminun mags on the market.
The US Army went with the green follower sometime in the 90's - it had a larger rear tab - but not a front tab - so it did not really solve the nosedive issue with mags. Since then they have been in search of a High Reliability mag - with attempts like the HK SA80A2 mag, and now in some units Magpuls PMAG.
Other have simply ordered new USGI mags - and put in the enhanced follower from Magpul.
WRT the general increase in reliability -- well one thing, if your unit has beat to shit mags and worn spring - even the enhanced follower really wont help that much.
For general increase in reliability - I never had a stoppage with my C8SFW, nor so far with my M4-Recce here or my 10.5" gun using the Magpull follower - maybe it helped - maybe not.
In Afghanistan with my M4A1 and stock USGI mags - I encountered several issues that where directly mag related (NIB USGI and green followers) - So I am of the opinion it helps. Since that same M4A1 was good to go with the magpul mags previously (I was leaving and gave my mags to buddies my last day at work- and went to the range for a last hurrah my second last day in country, using mags from our stores...)
It really comes down to you if you want a few % point of reliability for a few dollars. I do it - but it would not screw bloody murder if people with me did not. Thats said I dont know anyone with me running M4's that does not have them, or PMAG's (the HK mags got shelved due to issues).
-Kev
