I've thought about this a few times. I always go for in calls, but my mate nearly always goes for outcalls. He says that's because 1) he's more often than not had a couple beers so can't drive, and 2) if he books a girl for an hour to come to him, then she knows she's there for an hour regardless, so the service delivery is different (than a girl you've gone to visit, who, often, wants you in and out as quickly as poss)
But on the other hand, as fulhamfc said, you've given an awful lot of personal info away to a girl/pimp, and I'm not that comfortable about having people I don't know enter my house as it is - let alone a person who *could* be less than scrupulous (note, I'm not tarnishing ALL WGs as this, but we all know that some are like this)
Flip hands again though, and doing incalls means visiting places you've never been, and some that can be very suspect/dodgy - as a couple recent threads on here have highlighted. My biggest worry with a situation like that is being mugged/robbed on site, and although I don't take my wallet into WG's houses/flats, naturally I have it with me and left in the car. So being mugged/robbed and having my phone and cash stolen is one thing, but if they take my car keys, that has my wallet, house keys, etc etc in it. Bit of a problem if that happens and I'm miles from home with no car, keys, phone or cash!
Fuck, when you weigh it up like that, it makes you not want to do either!