I use the Nikon FTZ-II. I did follow the news of the Monster Adapter from the time it was first announced. I lost interest after seeing the early production unit reviewed by Matt Granger. There are a lot of limitations I noticed, in particular only screw-drive AF lenses can focus, and even then many are not supported.
I lost interest then and do not know if things have been improved significantly with new firmware. Nikon's FTZ does fully work with internal motor lenses, which is everything introduced after 2002 basically. And the older screw-drive type can be manually focused with focus confirmation and focus-peaking.