YepYou do lose folding capability while it's mounted, but it is quick detach and does retain zero. Obviously doesn't help much if you want to carry/transport your rifle folded and ready to rock (which you do IIRC).
Easily, and easily while incoming.... Different things.You can still easily remove the topcover and do a complete field strip with the optic mounted.
Balances good to me....little heavy on the front end points better.You can't go wrong with the Ultimak, but I prefer the side mount because the rifle balances better, the optic sits closer to the eye, and you can still easily remove the gas tube for cleaning (especially important when shooting corrosive ammo).
Optic farther out helps you see the whole area better.
I've been rocking corrosive ammo in the 74 with an ultimak... it's G2G.
YMMV.