As far as I know, Demco is the only tie rod steerable dolly, and is the best of the best. But not saying others won't work good.
Amco is a rigid frame non steerable dolly,...wheels are going straight ahead all the time, even around the corners, and while they seem to work, I myself wouldn't have one.
Rich
'01 31' Rexall Vision, Generac 5.5k, 1000 watt Honda, PD 9245 conv, 300 watts Solar, 150 watt inv, 2 Cos 6v batts, ammeters, led voltmeters all over the place, KD/sat, 2 Oly Cat heaters w/ ox, and towing a 2012 Liberty, Lowe bass boat, or a Kawi Mule.