A couple of comments on this:
1. SM Priority 0 is lowest priority and 15 is highest. You might want to set Intel switch SM to be higher SM priority than Mellanox/Voltaire switch SM priority.
2. Best practice is not to run different SM flavors in same subnet. There are many SM behaviors that are vendor specific and failover between the different flavors may be problematic.
Hope this helps,
-- Hal