The PTR has been out for several days now. It's loaded with the latest build of the upcoming patch 3.3 which will feature the Icecrown raid and several smaller 5 man instances. The first instance that's up for testing is the Pit of Saron. I know some players do not like to be spoiled and would rather take in the moment when they first encounter it on their own. Others like myself crave information and wish to know every possible detail on a particular boss or instance. There's no right or wrong answer. PTRs are designed to be a testing ground and it offers a cool preview of what is to come. Some of the other bloggers on the staff along with myself jumped on during the weekend to give the place a shot. I had a fun time in there and learned a few interesting things. I don't think the instance is entirely finished yet, but there's enough in there to keep me busy healing.
Have you taken a look around the place yet? If not, do you intend to at some point?