Up to you really, if you can figure out a way to change reforges for it you could grab it mid raid to try out and easily swap back. There isn't a Mastery cap though, other than the soft cap as Tungzten mentions, which is 33% of the casting Paladin's Max health at the time the last bubble was applied. Personally I run the Int 2nd BP 10 man style atm and I enjoy the speed compared to the 1st BP, but I do plan to downgrade after xmas when my guild comes off its holiday downscales, depending on gear upgrades I may stick with the 2nd BP or go down, either way though I will be swapping out Int > Mastery.