I have 2 of the 'generic' brand (can't even tell you what brand they are, but rated at 3.6T lift) bought through a local seller here where I live, back around 2013.
I had a couple of mates also interested at the same time and we were all concerned about the fact the hoists don't need to be bolted down, so the seller arranged for us to visit a guy with a hoist already assembled with a Lincoln Continental parked on it; a huge vehicle that overhung both the front and back of the hoist by a decent amount! It was all rock solid, even when the owner grabbed a ratchet/socket and started heaving on some of the front end components. Convinced all of us that everything was OK :-).
Since then I have been back for a second unit (as there's no such thing as enough space!) and the seller has probably sold 8-10 units through our group of contacts over the years. He's currently in Italy working on another project so unfortunately not selling them at the moment as far as I know.
Since installation I had to reposition both my hoists by a foot. The first one I unloaded and shifted everything - took half a day :-( The second one I got a decent block of wood and sledge hammer and moved each post an inch at a time. Half an hour later it was in the new position (still with the car on it) and never look like being any sort of issue.
Our units are pretty much the same design as the Tuff Lift ones, just standard height as 'extra height' hadn't been invented then ( but would be handy, especially for earlier vehicles), but the hydraulic set up is attached to the front left/right rear post, which sounds like would suit you better; so they do exist. (Painted blue not black too).
The main thing to look for is the double safety lock system. Some units only have a single locking system which you lower the hoist down onto when at the desired height. The second locking system is linked into the cable/hydraulic mechanism, which automatically activates if there is a failure; this probably is the main feature in the pass/fail for ADR.
Other than my second unit having a faulty capacitor when assembled I am not aware of anyone having any issues with any of the hoists. My units are basically for storage and get operated very little, but my mate has a usable collector car on/under his so it gets used as much as you would expect for this type of driver vehicle.
Assembly by two people would be ideal, but I did assemble both of mine by myself, using milk crates to support the runways off the ground during assembly. I used a couple of dollies to move them around. They are the heavy bits as Col has said. The posts are easily manageable by one person.
Needs a 15 amp circuit for 240 volt and assume all would be the same in this regard.
Hope this info gives you some reassurance.
Cheers,
JPXU1