I found the room OK. Nothing special, but nothing as bad as littleleaguemom's experience. Roomer larger than I'd expected. I bought the cheapest rate from hilton.com and I think I was silver at the time (but I did have a good record on scoring upgrades with silver status in the UK ).

My only complaint from my stay was the service at breakfast. While they were the only Hilton I've ever come across which has offered a smoking section at breakfast the service from breakfast waiting staff was frankly hopeless. Slow, forgetful, etc etc etc. Not the best thing in the world if you're grabbing a quick bite before a flight... (FWIW the majority of rates at UK Hiltons normally include breakfast - although I don't know whether this applies to an award stay).

The hotel is connected to Gatwick (can't remember which terminal) by walkway, so no need for a shuttle bus. If you're needing the other terminal there's a very quick and regular airtrain thing between the two.

littleleaguemom is spot on about getting into town - Gatwick Express is by far the best option. The airport's actually quite a way out of town (but only takes 30mins on the Gatwick Express). If you're staying for more than one night for an early flight, I'd recommend staying more centrally as it won't be much more expensive (and if you get the Metropole on a non-conference day it'll probably be cheaper!). NB that the Gatwick Express is not a 24hr service - nothing from London between 00:30 and 04:30 or in the other direction between 01:35 and 05:20.