First of all, Awesome photography on your website! Very cool stuff.
Secondly: We used a KarKaddy 3 with surge brakes for the first 3 years (a Prius was our toad). We liked it and it worked good. We have since bought a Jeep and tow 4-down now. I could go back to a dolly if I had too. But it is nice not having the dolly at the site though. Also, if we ever take a corner too tight or run down a dead end road.... it seems like the detach of the 4-down method might be faster and more efficient than dealing with a dolly.
Check out craigslist if you decide on the dolly route, you might find better prices there. We sold ours in 24 hours at a $1,500 price recently. It was in good condition and maintained when it was supposed to (greasing the zerks).