MR Ts Haircut
For me it all goes to logistics and Familiarity. Use what you train with. Use what you can feed. I reload 5.56/.223 and for pistol .45 and .40 My personal choice is the AR15 with a 1×4 scope with an incorporated red dot. Of course BUIS. I simply prefer this round and with its use by LEO and militaryit will be available. The 5.56 is ideal for home defense and is unlikely to overpenetrate. With the 1×4 I can reach out to 300 yds and it is good for CQB.
For Pistol, I prefer the 1911 in .45 My Springfield Loaded fits the bill. For the .40 I prefer the XDM because of the stopping power and the round capacity (15 rds Mag).
that is my choice and what I will go with.