Normally, I stick to to the 150-200 range in London, though I always try to check one off the higher end (350ish/hour) checklist once a month.
The most ever was a one a few years ago after a few weeks of feeling like crap (messy breakup with the gf at the time). Was with some mates in Vegas for the weekend, and 2 grand (dollars) on 2 hours with Angelina Valentine back when she was insanely hot and without the crazy tats.
Was everything I thought it would be, punt of a lifetime.
Hopefully, another such opportunity will arise when I'm in Vegas later this year