"Better" and/or "Best" are mostly matters of opinion.
IMO, the best is a steerable dolly like the Demco Kar Kaddy.
Next best, IMO, is a dolly with a turntable for steering, such as the American Tow Dolly or the Master tow.
The worst, IMO, is a dolly that has no steering capability at all.
As for brakes, there are only two choices, based on the operating system:
1. Electric brakes, identical to electro-magnetic trailer brakes. These systems require a brake controller, either trailer mounted or mounted near the driver of the towing vehicle.
2. Surge brakes. These are hydraulic brakes, and can be either drum or disk type.
As always, some folks swear by a certain type, either the dolly or the brakes, other folks swear at them.
