I like it, food has been greatly improved over the last year, accomodation a little outdated though and the bunks have a ridicilous amount of headroom on the bottom bunk so be sure to take a smaller teddy. The assualt course is good and plenty of long dark roads.
When I was there, there was a gym [it was fairly small], although you had to wait for a gym induction before you could actually use it (probably half-way through the week, at a time you can't make due to lessons). There were a few run routes around, but it'll be dark by the time you get out... Ask the guard room for advice on a run-route, and do some routes with a buddy. If you get bored of running, do some interval training and mix in some press-ups and sit-ups!
Things to bring;
A couple of years ago there was no NAAFI open and no washing machines. (Although there was a newsagents nearby, and a laundrette in town). Disappointingly the laundrette was closed before you were released from lessons in the evening (unless you're an ED and your day finishes with an hour long brew break at 3pm!). I'd bring some cleaning stuffs for you to wash your C95s in the sinks ...
If you've got a laptop, it's great for note-taking (if you're that way inclined) ... the DS may even be happy for you to transfer some of the powerpoints onto your computer, if you bring a CD or USB stick [but you'd better ask Polar?], and a laptop's always great for a bit of RnR if you stick on some music or a DVD.
As Watto says, plenty of stationery (for both note-making and revision). Make sure you've got A4 pads, and not the issued pocket books ... you'll fill a pocket pad up in half a day!