Over the past few years there have been just under half a dozen on my top 2 list at various times.
Some have fallen off while others have come along and risen to the top....a couple have stayed on the bottom.
My criteria are based on attitude, reliability, fair treatment and respect of employees. a sense of humour and a genuine friendly reaction to your call.
Number one by a mile is Mike @ GoodGirls
All of the above and he takes pre-bookings and will call if a girl is a few minutes late....but they are almost never late.
Second is Frank from Delight....a pleasure to deal with.
Honorable mention to Lola of MGF