I too have wondered if anyone out there is using Blue Ox's version of ReadyBrake, the AutoStop. Have not seen much discussion about it.
$665 for both a Blue ox Tow bar AND Auto Stop is an absolute steal, IMO. The Readybrake unit that includes both (ReadyBrute Elite) costs almost twice that much (although I believe the Readybrute tow bar is probably a bit more stout than a Blue Ox Alpha).
I do recall when looking closely at the Autostop unit, I liked the way they routed the cable on the tow bar a bit better than Readybrake's design. However, on the flipside, it seemed the Autostop had a lot more moving parts internally that pulled the cable, that could possibly be a bit more failure prone in the long run. Impossible to say, though, without some specific owner experience.
I do know, as already said, that the Readybrake unit is great, simply works and works great. Have had it on two different vehicles now, and wouldn't want to own anything else.