We used them a year ago.
The driver managed to creep out my mother in law with his constant flirting with my four (!) year old daughter. My mother in law found it very inappropriate. I thought it was weird, but wasn't as disturbed.
At pick up, the driver was late, even though we called to confirm. When we called, the operator told us he was just there, but had left because we weren't - we'd gotten out fifteen minutes before hand, he had two cellphone numbers plus could have asked the front desk at the resort. He then took us the long way to the airport - we didn't have a lot of leeway in catching our plane and only because we got the best skycap I've ever seen (who got the biggest tip we've ever handed out - $50) managed to avoid the airport 1000 m dash. We arrived at the gate while they were annoucing seats - and I'd given myself two and a half hours from WDW in the original pick up time.
I hope they have gotten better, but we won't use them again to find out.