A couple of weeks ago, I promised that I'd return to priest PvP once the PvP-related problems on the Cataclysm beta were resolved. Things still aren't perfect either for balance or testing, but I have more information now than I did two weeks ago, so I'm willing to take a stab at it ... /bleed. Or take a stab in the kidney or something.
Overall, I'm going to say things aren't looking too great. I don't think you should panic, granted, but things are pretty rough for priests right now. Mana is a nightmare, options for spell selection suffer due to mana restraint, dispels are essential but you can't afford to cast them, and interrupts and crowd control run rampant.
I'll elaborate on all of these in a bit, but before I get started, I want to take you guys back to December 2008. Wrath had just come out, and the start of Season 5 was on everyone's minds. When at last it came, there was a deafening thunder as tens of thousands of priest bodies crashed lifelessly to the ground. Playing a priest was like not playing at all because of how fragile we were (unless you were one of those cheap holy priests who exploited the Glyph of Spirit of Redemption for a short while.) The outcry from the community was one of the more unified responses to priest class balance I have ever seen, as both novice and gladiator turned to Blizzard and screamed a resounding, "WTF?!"