I love the M10 rings, all my rifles have moved on to M10 rings, including my .300NM.
Very simple setup - I much prefer having to deal with one screw per mount when leveling my scope then 6+. It's a very clever design that makes it easy on the end user, and they work.
Spuhr is great, though I've never bought one as I personally don't want to deal with the 12+ screws, and don't see the need to pay the price over say an M10.