I love the M10 rings, but am well aware that Spuhr makes an excellent product as well. You might ask yourself if there is some tangible benefit from spending more than twice the cost of what are already some very expensive rings. With the one-piece mounts with elevation I can see a benefit, on the right rifle. (And would also note that ARC makes a one-piece mount with elevation for under $300.) But for just rings, or where rings are more than adequate, I can't see a benefit to the Spuhr mount.
Disclosure: Own three sets of ARC rings, one M10, two M3. Don't own a Spuhr mount, did "own" one for two days but that's a long story. It was obviously well made.