I'm the sister.... and my research has shown that Payless Transportation has the lowest prices, but I can't find much feedback on them. (We have another message thread going on that... but not getting any hits.) I also found Tiffany Towncar - which appears to be just slightly higher than Payless, and there's a few threads on this site that speak favorably of them.
Southern Elegance was nice and timely, but definitely more expensive than some of the others.
Southern Elegance was nice and timely, but definitely more expensive than some of the others.