I don't have a lot of experience in this area but for what it worth here is some info.
I've never used Dependable (DAS) so can't comment on their service but can tell you a little about their prices. I got quotes from them that were way above any other company. Even with a $50 ebay discount. (not much of a discount on a $1600+ quote. I've received the same feedback about the pricing from other people that got quotes from them as well.
I got a quote from Passport (FedEx) that was almost $400 less for door-to-door enclosed transport for what DAS wanted for Open trailer top load. The closed transport different was over $600. DAS couldn't ship for over 1 month, FedEx within 1 week.
Not exact prices but it went something like this.
DAS - open trailer top of the trailer was $1400
DAS - enclosed trailer door to door $1600+
Passport/FedEx - enclosed trailer door-to-door $1000
Top of the trailer on an open truck is a plus to avoid a lot of debris kicking up on the car and if the car above you has a leak it has nowhere to go but on your car on the bottom.
FedEx came recommended from people that have used them in the past and had good experiences.
FedEx:
http://passport.fedex.com/
DAS:
http://www.dasautoshippers.com/
You might want to try this site too to get some prices
They will send you a bunch of emails with quotes for reference. Most initial quotes are basic open trailer prices.
http://www.moveavehicle.com/
Keep in mind most companies are charging a fuel surcharge right now which ranges from $100-300.
Good Luck!