Went to the Red Lion for 08 & 09. The best part of the Red Lion is the bar they have right under the hotel called the Elephant & Castle. Having your hotel room right there after a night of debauchery is extremely convenient. Being able to crawl from the pub to your hotel room at 3am is very nice.... not talking from experience of course...
However, we had issues with the Red Lion in 09. First, they canceled one of our rooms on us (our group needed 2 rooms) and didn't tell us. We were able to get two rooms eventually, but the other group had to switch rooms on Friday which was a huge pain. They also shut off the water for the WHOLE hotel on Saturday which went as well as you'd expect.
Tried the Sheraton for last year (10) and it was way better than the Red Lion. The rates were the same if I recall, and we didn't have any trouble with rooms. It's also directly beside the convention center, so swag drops are very easy to do. One of our friends did get trouble with hotel bookings, but they took care of him very nicely. I believe they upgraded him and everyone else he was staying with to the presidential suite at no extra cost. The Sheraton is also only short walk away from the Elephant & Castle... so we just had to... I mean I'd assume you'd just have to take a bit more time to crawl away from the bar late at night. Not that I would know being a fine upstanding citizen.