It's worth visiting but if punting's the priority then Hamburg will be a big disappointment.
I did go to the massage place in the end. Quite a nice old building opposite the Berliner Tor U-Bahn stop with a discrete extrance off the street. The receptionist said hello and told me the prices, I think it was 90 Euros for one hour 'erotic massage' with happy ending (no actual sex is on offer), then brought the ladies in to introduce themselves. None of them were stunners and quite a few were mature types, I got the impression that the girls here are actual proper masseuses who do a bit of sex work rather than sex workers trying to pass as masseuses. I chose one of the younger looking girls, Spanish with nice curves and English speaking. She led me up to the room, which was inside some kind of old tower with a spiral staircase. A very unusual old building but nicely done up. Once inside the room I was told it's 150 Euros if you also want body to body and touching, which seemed misleading and expensive, as I assumed body to body would be part of the atandard erotic massage. I paid up though and I must admit the massage was excellent, she had obviously received proper training and was skilled at her job. I have no idea how long the vanilla massage went on for because I was completely focussed on just enjoying it, but eventually she asked me turn over and started with the B2B. A few minutes of rubbing her oily tits all over me followed by a few minutes of an oily handjob, then back to the B2B for a bit then back to the handjob, all the while I was exploring her body and pussy with hand. After a while she stopped with the B2B to focus on the happy ending. At this point I was really worked up and her hand felt amazing, so it didn't take long for me to finish.
So I did have a good time here but I'm still a bit peeved about the lack of transparency on the pricing, and the selection of ladies was a bit disappointing. I'd probably go back but I suspect there might be better places in Hamburg if you know where to look.