Sorry, forgot to answer the OP's actual question.
We were all set up to tow our automatic Mini on a very lightweight trailer until we discovered we had rear axle weight issues. (Disclaimer: I have towed boats and TT's for many years, but I do not have personal experience towing a car on a dolly). Anyway…….
We also had a new Ford Escape, so we decided to flat tow the Escape. I can hook and unhook the car in approximately two minutes. Flat towing has turned out to be so convenient, we will never consider any other alternative. We have a SMI Stay-in-Play brake system (semi-permanent installation), so all we do is attach the tow bar, plug in the electrical cord and flip a switch on in the car. It is fast and easy. Our installer added separate bulbs in the rear taillight assembly, so our towing brake/turn signal lights are completely independent of the Escape's lights.
Two major considerations are:
1. The initial setup cost is kind of high - if your vehicle is newer and you intend to keep it for some time, then the cost is much easier to stomach/justify. We generally keep our cars upwards of 10 years, so we felt the expense was worth it.
2. As mentioned previously, you can't back up with four down, so you have to plan accordingly - usually not a problem - gas stops in particular are more carefully planned. In 17,000 miles of flat towing, we have only had to unhook once - I missed a turn and we did not know how far we would have to go before finding a place to turn around (country road in the middle of nowhere).
A friend of mine used a dolly and once he saw how easy our setup is, he traded in his existing car for one he could flat tow and absolutely loves it.