I used the service at the Contemporary about two years ago when my boy was 11 months so we could hop over to the MK for the EM hours. there was a minimum of 4 hours and a $10 traveling fee. If i remember correctly it came up to $70-$80ish for the night including the tip.
We booked this service and got ready when it was time, knowing that if we didnt feel comfortable with the person that was about to show up that we would turn the service down. Fortunately the woman that showed up spend 15 mins talking to us, answering questions, and really put us at ease. Our sleeping little boy was in the same position when we got back.
Of course $70-$80 is rather high for one child for 4 hours but we thoroughly enjoyed the night out and dont regret it.
However, now we are taking a different approach. We have two young boys (3 years and 6 months) and we knew that our up coming June trip would be hard with the baby and limiting for the 3 year old. Plus we knew that if we wanted to get out for a night or two that the babysitting service would cost an arm and a leg because its two kids this time. Anyways, we made the decision to actually bring a babysitter/mommy's helper. She's a dear family friend who is a kindergarten teacher (CPR/first aid, knows how to handle potty issues and tired toddler) and we're excited that she's coming! We know that we can go out in the evenings when we want, we can ride a ride with 3 year old, we can go to the PPP with the 3 year old without having to birng a 6 month old, etc etc. We did the math and figured that the freedom is well worth the little extra (just park passes and food....hotel is the same price (DVC) and we used airline miles).