Well, I'm issued both a 6906 & SW99 (.40 S&W) ... and I often carry the 6906 off duty ...
On the other hand, I own several other S&W pistols which I'll occasionally carry off duty (CS9, CS45, 4513TSW, 4013TSW, 3913), as well as a 642 J-frame, which has become my most frequent off duty weapon.
I find it's easier to remain with the same general operating system on my frequently carried weapons, which is one of the reasons I "semi-retired" all of my 1911's to the safe, and only take them out for frequent practice, but don't carry them off duty anymore. (That may change, though, if I'm issued a 1911 in the future). I find it's simply easier to stay with the same basic configuration of weapon for both duty and off duty. The revolver is an exception ...
My issued ammunition is currently Winchester 127gr +P+ RA9TA in 9mm and 165gr RA40TA in .40 S&W ... and I carry either the Winchester 230gr RA45T or Speer 230gr Gold Dot in my .45's. My .38 ammunition has traditionally been one of the different versions of 158gr LSWCHP/LHP +P loads, although I've been testing some of the 125gr +P Gold Dot and 130gr +P SXT .38 loads, and I have some of the new Speer 135gr Gold Dot +P on order (I liked the way it performed in a gelatin test we tried it in last week).
If I wasn't presently issued the Winchester T-Series loads, I'd be perfectly comfortable carrying one of the excellent Speer Gold Dot offerings in all 3 pistol calibers ...
Naturally, I practice a lot with all of these weapons, and some other non-S&W weapons ...
I've been told that I qualify for the "gun of the month" club when it comes to all of the personally owned weapons I have on my qualification list ...