Real time with pause when I know the fight is not tough. When I know using abilities and a lot of spells is not necessary.
I immediatly switch to turn based when the fight is tough, some kind of bossfight. It is way easier to position the party in correct place, time the casting and use of abilities. It takes some time, sure, but it is for me more interesting.
When only one option is available, and not both as in pathfinder I prefer turn based, more so when the whole ruleset is turn based.