I bought the Tippmann M4-22 Elite, a couple of weeks ago. I've put about 400 rounds through it. I'd score it about an 8.5 out of 10.
The all aluminum construction is impressive. Its accuracy and handling qualities are excellent. I've yet to experience a failure to feed, although most of my ammo has been the reliable CCI Mini Mag.
I do not care for the clumsy magazine cover jackets, which do nothing to enhance the rifle. Its impossible to know how many rounds are in the mag stack without pushing the finicky button to lower the concealing jacket. Also, every Tippmann I handled at my LGS, and the rifle I purchased online had a distracting rattle in the stock. The Tippmann manufactured stock simply does not ride tightly enough on the buffer tube. I replaced mine with a MagPul unit. Problem solved, albeit at added expense.
My S&W 15-22 is a few ounces lighter, given its polymer build. It is also a reliable shooter and priced about the same as the Tippmanns.
I'd give a slight nod to the Tippmann, but both rifles offer satisfying plinking performance. I am not likely to scope either of these rimfires. Out to about 50 yards, both offer fine performance with their stock sights and versatile features.