I didn't do a speed test, but I'd add the W Atlanta Midtown to this list based on my experience. They use a provider (Superclick) that rewrites nearly every web page to insert an obtrusive banner at the top showing session information; it's impossible to get rid of it permanently. And the company in question has been known to sell data on sites browsed by hotel guests for advertising purposes.

That, and it was so slow I couldn't watch a short YouTube video in the middle of the afternoon.