Thanks Betsy, so that's how you minimize your risks. What a great site, I'm going to try that for other cities. From your experience, did you feel that you're treated the same as other guests, such as getting a room that's agreeable to you?
You're spot on about energy in Potsdamerplatz!

Thanks, everyone, for all of your thoughts and suggestions. Lots of decisions and research to do... but I'm really looking forward to it.... Prague and Hamburg both seem like god choices. Any thoughts on Frankfurt?

Skip Frankfurt Joe, seriously!

DAX, we were treated absolutely no differently from the other guests as far as I could tell. Our room was fine and it was in a good location in the hotel. Priceline was never mentioned. The front desk staff were delightful to us, as was the security staff who repaired our in-room safe (but that's another story). There were coffee and skippable pastries in the lobby every morning, a nice touch.