I have the MC on STick and the Audiovox on lipSTick. Bought my MC years ago (95) for ~$300. Far as I know, the unit has changed very little. Works as advertised. The cable combiner thingy is a PITA when trying to put the fake tank back on (ST1100). Don't know how they did for the 1300. Mine is a near original unit, the vacuum and 'puter are two pieces,,, newest ones are all combined in the servo (just like the Audivox).
The Audiovox CCS100 is virtually the same unit but ya gotta finagle yur own "cable combiner." The options are endless, I've installed several using various connection methods. On lipSTick, I add the lever on the bell crank and fastened the cable anchoring point to the air filter housing with self-tapping screws. Far as I know, that's unique.
Functionally, both work the same. On my MC, the cable pulled out of the servo diaphragm after about 100,000 miles. I was able to dismantle and fix it. On the Audiovox, I've had recurring problems with the (not waterproof) switch unit. Also had (have?) a problem with the power wire at the connector on the servo. It's intermittent and has left me CCless a couple times but it's working fine right now.
If I was gonna do one today, I'd get the Rosta all-electric. Smaller and easier to "stash".
Audiovox, $15 to $115 depending, and some finagling.
MC, $1000+ but a quality unit and they've done the finagling for ya.
Rosta, $350 to 400ish, more finagling than the Audivox but it's been sorted by our fine crew scientiSTs at ST-Owners R&D.
Ya buys yur ticket and ya takes yur chances.