I've own 3,
1)ARMS #18, no the best one, but the lower in profile, so it is still my #1
2)Smith Enterprises, the best or most solid of the 4 also the heaviest,
3)Springfield or copy, Very flimzy, gadgety mount with cheap metalurgic properties,
I'd like to try the SadLak Aluminum or titanium/lightweight model, seems rugged.