Got mine yesterday from B&H and i'm in love with it. Super fast and accurate but trying to focus into infinity when the lens in not caused a little bit of a freak out. Restarting the camera got it back to working.
How fast do you call "super-fast"? Even after updating to firmware 2.0, it takes about 2-3 seconds to focus from infinity to about 2-3 meters with a 35 or 50mm lens.
PS: Like me, you own a Deo-Tech version of the TechArt - and B&H has stopped selling it. Apparently they gave up on getting enough supply.
Here is what is truly curious: which company actually designed the adapter? When I tried to get support from TechArt, "David" replied that I should contact Deo for support - which I did. There appear to be 3 corporate entities involved - Deo, TechArt and MX, a Hong Kong distributor?
The Deo web site went into more detail about the firmware 2.0 upgrade - claims it has eliminated all but 5% of the blackout condition that occasionally occurred when pressing the shutter button, and they are working on that.
$400 is a lot of money, and I struggled whether I should keep or return this adapter. It is a battery drain - not terrible - but it does a remarkably accurate job of hitting focus with both my pre-aspheric (~1982) 50mm f2 Summicron-M and 35mm f1.4 Summilux-M. While no focus-speed demon, it appears to work a bit faster and more effortlessly than MF, leading me to use my M mounts more than I would - which leads me to a more compact travel kit possibility. I still carry a Yeenon helical M to FE adapter in case the Deo/TechArt might fail.
And so, even though B&H has given up on it, I decided to keep it.