I think it's pretty important to remember that your mileage may vary. A good time depends on both parties.   Witness these 2 reviews of the same provider in the same month. What's the variable?  The reviewer.

          Appearance     Performance
Jan 2002   3 - Homely     3 - Barely worth the effort
Jan 2002   8 - Really Hot 8 - Went the extra mile

FWIW, for those less experienced you may wish to check the other reviews from the same reviewer to see if their taste parallels yours before making an appt.