I did all this investigation last year.
A dolly with brakes is mandatory in some states, and is a safety issue. I can feel the dolly brakes as they apply.
I ended-up with a Master-Tow dolly off of CraigsList. Ran me $800. It's in good condition and had new 4-ply steel tires. I re-greased the bearings and adj'd the brake shoes and purchased a progressive electric brake controller. I ran heavy wire to run the brake voltage 45 feet from the cockpit to the hitch. TTL investment maybe $1100.
Works perfectly and reliably...about 8000 miles so far.
I tow a Mercury Mariner Hybrid...about 3600lbs.
2014 XLR 415AMP, 2011 F350 6.7 DRW, restored 82 Wing, 02 Shadow, 06 ST1300A, NRA Benefactors.