The Spuhr mounts are expensive, but give you a few more options with the extra mounting points on the mount itself. No shift in zero when mount is removed and reattached. The simple leveling wedge works very well.
If you decide on a Spuhr mount, I would advise that you buy a cantilever mount. You don't need a mount with a bubble level unless you are shooting at long distances. Also with an AR, your eyes will be so close to the rear of the mount that it will be hard to clearly focus on the bubble level.
I started with the 30mm model SP-3016 on a DDM4 with a Steiner T5Xi 1-5. But quickly found that the eye box was too tight, especially when shooting prone. I needed the scope positioned further forward. To accomplish this, I switched to the 30mm model SP-3026. The SP-3026 has a longer cantilever, but it is also 6mm lower, so you won't be able to use any backup sights.
Take a look at the
QDP-4016 for the new quick release version.
QDP-4046 quick release.
Original
SP-4016 with bubble level.
SP-4026 no bubble level, longer cantilever, 6mm lower.