I ran a TM P90 for a season, one of the straightest shooting AEGs I'd owned, and the ROF was on the silly side of awesome. I don't regret selling it. Mags are a pain to carry, reloading is a breeze, but storing spent mags required a finesse that had to be learned really slow to get it right. It is the best SMG/LMG ever. Real cap at 60ish rounds was nuts.
I also had to build a custom twist lock kydex insert for M4 pouches to carry 8 magazines in an 8 magazine M4 rig. It worked well but the mags ended up hitting me in the face if I was supine.
Ár skal rísa, sá er annars vill
fé eða fjör hafa. Sjaldan liggjandi úlfur
lær um getur né sofandi maður sigur.