I very strongly prefer playing and DMing in published, commercial settings. I strongly agree with many of the points raised by Gizmo in this thread, and I do understand that it's not really a popular position.
The homebrew campaigns that I've played in have been uniformly disastrous. Every session, I got the uncomfortable feeling that every aspect of the setting was in the DM's head, but we didn't get any of it. It was like we were being run through someone else's imagination but we had no idea what was going on.
One campaign, the DM had (seemingly) a pretty detailed world. There were many different nations with their own cities and cultures, but the problem was, we the players didn't know any of it. There were no maps, no background, no knowledge, no anything. The DM might have just been making everything up on the fly as we went.
I want, as a player, to have some basic background knowledge of the geography, politics, culture, customs, etc. of a setting before I play. Well-known published settings do that and establish an equal footing for everyone. Good homebrew settings might be capable of that, but honestly, I've never encountered it.