My personal favorite is the L86A2, mainly just because i think it looks cool honestly.
But what is your favorite MAG fed lmg, not belt fed.I think it depends on your style of play. Speaking from my own experience, I've slowed down my pace, so whereas I thought DMRs were crap, now I use them all the time. That said, I think M240/M60 for close range (Metro/Lockers,) RPK-12 for Medium-range (Pearl,) U100 Medium-LR (Propaganda,) and M240 bipod with optics for large open maps.
If your style is run-until u spot enemy, then you would certainly know better than I - but I don't think that is how "belt-fed suppression tools" were meant to be employed.
I started paying attention to the amount of time that each enemy encounter takes. Your belt-fed at a distance (on the snow in Lockers,) Is no match for a well-disciplined DMR shooter. Unless you are on a bipod, that is - since that is its "real-world usage," well implemented in the gamecode.