Rodney,
Most of them are in Europe. As far as I know, Unicat invented the design and has proofen itself for many years. Others have tried copying them, many have failed. As you know, our engineer in Germany has a great track record designing them. The difficult part is the mechanism, guiding system, wall build up, weather proofing and part sourcing.We are currently helping several customers with the design of a lifting system.
But to answer your question:
I would recommend Unicat, Archemobil and GXV . Bliss just came out with one too, but as with everything else, I would like to see how they perform 5-10 years down the road.