Just returned from Prague.  I stopped by Sweet Paradise one day and was extremely disappointed - there were only 4 or 5 girls there and that's exactly what they were - 4s or 5s.  Maybe I just got unlucky and if I'd come back later or the next day it would've been crawling with 9s and 10s, but that one look was enough for me.  I think the better bet is to try the privats (i.e., brothels run out of apartments), although you're taking your chances there, too, because there is often only 1 or 2 girls to choose from.  The one that seemed to have the best reviews is Privat Nebe, so I went there one day - there were 2 girls, one of whom was pretty skanky and spoke no English, the other was 22, Czech, drop-dead gorgeous and spoke English.  Not surprisingly, I chose #2 and had a great time with her (1500 czech crowns (i.e., approx. 85 bucks) for one hour, including BBBJ and multiple pops, but this girl didn't kiss or CIM).  There's another popular privat called something Studentzka - I stopped by there twice. The first time, just one girl working who didn't appeal to me so I left.  The second time, two girls working (one of whom was the the girl from the previous time) - I chose the other girl, German, 30, spoke a few words of English, probably an 8, and lots of fun (1200 czech crowns for one hour, including BBBJ and multiple pops and kissing; CIM (swallow) was an extra 400, so that's 1600 czech crowns total, a little over 90 bucks).  The prices at Sweet Paradise are higher - closer to 2200 czech crowns, I think - but that's beginning at 8 p.m.; earlier than 8 p.m., the prices are more in line with Privat Nebe, though I can't speak with authority on the services since, as I mentioned, I walked out.

None of these experiences come even close to matching the FKK experience, in my opinion.