In my opinion, Blair Street ("BSS") is a better sauna than London Street ("LSS").
The service at BSS is better and more intimate - OWO, DFK, cunnilingus etc - Paula, Heidi and Daisy particularly.
LSS is good and I would say the girls are very attractive (and mostly Romanian), but when in the room, the service is lacking and really not that intimate at all - I've often left thinking that was a waste of money, given that I could have went to BSS 10 minutes up the road!
I do, however, appreciate that saunas are a subjective thing - This is just my opinion from personal experience.