I played PVP for 3 years and the reason was that I felt that, originally, I would be missing out on an aspect of the game without the ability to just go out and PVP at any time. But over the years I found that what I was really missing out on was a nice sandbox mode outside PVP where I could play when I wasn't in the mood, and there was NO WAY to get that on a PVP server. Spending hours and hours in battlegrounds and arena was plenty of PVP for me.

Anyway, I did play horde and alliance on a PVP server, and it was always equally bad on either faction. It's easy to develop a seething hatred for the other faction and think that the people you're playing with are better than that. It's not the case.