I do both.
I mainly use homebrews, which are, unmistakeably, an amalgamation of anything I find to be 'super cool' at the given moment.
However, I've run at least two Forgotten Realms games in the past and I'd love to run more. I'm also really into Eberron and I hope to run that someday (or play in it!). If/When the Iron Kingdoms Campaign Guide comes out, I'll see how much it vibes with my tastes, but so far, it's left me a little neutral.