Four Down or Tow Dolly

4 down if you have a vehicle capable of being towed 4 down. check the owner's manual, which is the only valid source of information. you can get "hints" from various other sources however.
bumpy

I started with a dolly but now tow 4 down. I like 4 down better. But as some have stated you may want to tow with a dolly if your car can't be towed 4 down.
Bill

4 Down. Backing can be a problem as stated. If I get where I need to back up I just unhook the car. Have only had to do that twice in 17 years. The wife and I can rehook the car in less than 5 minutes.

4 down ...did the enclosed CH. Never again

I've done it both ways and much prefer 4 down over a dolly.

All have some kind of a drawback, but towing 4 down has the least drawbacks and most positive features. Been towing 4 down for over 10 years of fulltiming and have had to unhook once to turn around and reverse directions.

I have only towed 4 down. When we bought our DP it already had a tow bar on it. Getting our 2012 Malibu ready for towing was about $1,000. After crinkling up the hood on the Malibu I learned that backing up was a bad idea, even a few feet. Besides redesigning the body shape on the Malibu I like towing 4 down.

The reason you can't back up when towing 4 down is the same front end geometry that makes the front wheels track strait ahead will try to turn them 180 degrees to the back. This has the potential to damage your car and the tow bar.
Bill

Just started towing and I am towing 4 dowm. I have Blue OX basepalte and towbar and use SM Stay-in-Play. So far its been pretty good towing even in the mts

We just started towing 4 down this year. Except for hills and parking, we hardly noticed the tow vehicle while driving. We are happy with our decision.
We seriously considered a tow dolly. It would have been cheaper but we liked the convenience of 4 down. It is easier to hook and unhook and the storage needs are less.
We installed a Blue Ox baseplate with their new, Avail towbar, an SMI stay an play duo braking system and a fusemaster disconnect switch which was needed for our CRV. It cost $3800 to have this system professionally installed. Many cars, like the 2015 CRV, cannot be towed 4 down so that may impact your choice.