I can't tell you about the SG550 since I havn't used it enough to form an opinan. But the m416 is an awsome gun. USing the gun scoped in is the key as to why it's so expensive. It's pretty much an m4cqc, without wasting money on supply cases. This gun is moderatly powered, fast firing rate, low recoil and just looks sweet. You put all that together and you get one hell of an expensive gun.