We just returned from a stay at WDW, and used Fairy Godmothers, based primarily on info we had from this site. Julianne (I believe) was our sitter - an 18-yr old. While we'd requested "Vera" (based on forum feedback) and were told that we'd probably get her, we were not upset at all to have Julianne. We'd heard of her on this forum (her mother has been an employee for quite some time), and she was a very polite young lady, and clearly capable of handling our 2.5 and 6-yr old girls.
The only negative was that both times that I spoke to the woman who (I believe) owns "Fairy Godmothers" she was on a cell phone, and I think I only had half of her attention as she was driving. When I booked with her, she quoted the rates, and I asked about the higher late-night rates. She explained that those only applied if your sitting didn't START until late in the evening, and that once you started at a rate, you just paid that rate until you were through with the sitter for the evening. I said "OK, I just wanted to check since we're planning to spend the evening at Pleasure Island after our 6:20 dinner". I thought it was strange that she never asked how LONG we'd need the sitter, but she DID say "you just pay at that rate until you're through with the sitter".
Well, when Julianne came to the room, I did tell her it will probably be a late night since we're going to Pleasure Island. She said that was fine, but clearly said also been given other (wrong) info from the owner. Because at 12:15 (a.m.) Julianne called to ask when we were coming back - that she had class the next morning, and was worried about driving home so late at night. We then learned that she had been told that we'd be back to the room around 9:30pm!! So we didn't linger long, and hustled back to our room, though it took awile to get back to the Beach Club Villas. We tipped her well and all, but it turned a great evening out into something that left us feeling guilty.
Looking back on it, I'm not sure I'd have done anything different. Now that I know, though, I'm going to be VERY CLEAR when we schedule the service that we'll be out until the early moning. I thought I'd made it clear that it was going to be a long night (Pleasure Island after dinner, worried about "late night charges", etc), but I obviously wasn't clear ENOUGH. Where she ever got that we'd be back by 9:30pm, though, I don't know. That's where I think the whole "talking on the cell phone while driving" came into play. I suspect she got me confused with someone else by the time everything was written down.
So to make a long story short (sorry, it's too late for that, isn't it?), just be VERY CLEAR on how long you intend to need a sitter - both at the time of the "booking" and when the sitter arrives. Lesson learned on OUR part!