Good Choice, I have a 6P with retention ring, and since I use it with my support hand, it moves with me from my 1911 to my AK if need be.

Reason I asked, if you were to stick with the 552, and forgot to turn it on/change the battery regularly, and got into a confrontation, you could actually use the corona and hot spot of the Surefire as a crude sighting device, if it's weapon mounted.