The one I brought. ...because it's what I have available.
That may sound a bit sarcastic, but it's a serious answer. If I don't trust a handgun, I don't use it. I have both revolvers and semi-autos that find themselves on self-defense/home-defense duty. I don't prefer one over the other, in general. On a trip, there are a lot of different factors that can influence me, as to which handgun I decide to bring.
Sometimes, it might be consideration of what a state I'm traveling through defines, or doesn't define, as "unloaded", and the requirements that go along with that. Other times, I grab whatever hasn't been on a "field trip" for a while. Other times, I might grab something specifically for its magazine/cylinder capacity (generally a consideration of wildlife in the area - not a preparation for fending off a flash mob). And, other times, I might grab something for its simplicity (DAO S&W J-frame comes to mind).
What I can tell you, for certain, is that if some one were to break into my house and come after my family
tonight, I would be working the J-frame (simplicity and reliability) and my wife would be running a Ruger P-95DC (simplicity, reliability, AND magazine capacity
).