Hi Axel - I really like mine. I think it works great for the price point, and if you've ever tried using regular bubble levels while moving you'll appreciate this unit. You still need bubbles to balance your sled and zero the Wagner of course.
It weighs next to nothing, much less than a pound total. The stats are probably on the Tiffen page. Not a concern.
In terms of powering it, I'm using the P-tap off the AB. Found this seller on Amazon that uses genuine AB plugs and 2.1mm connectors. Length can be a little flaky so it's worth an email to him/her to ensure you get the right thing:
Much cheaper than Tiffen, and last time I checked Paralinx wasn't carrying them anymore. They only had USB-2.1 connectors. May have changed in the meantime. Just check the polarity, even though the Wagner is protected.
Frederic Sturm gave me the great idea of using a spare monitor mount on my Zephyr, and I mount the box right behind the post on the top rod. Very solid connection. There's 8-9 parts that comprise the mount - if you have a Zephyr and are going that route I can probably find the invoice with the part numbers. I know Frederic had some issues getting all the pieces/parts through Tiffen UK, so I followed his advice and sent a nice clear picture to the folks in LA. Was under $50.
I think there's also a thread on here where Tom Willis mounted the box vertically off the post, so that could be another option with a fairly cheap bike tube or handlebar mount with a 1/4x20 bolt. Lots of options out there. I would personally not recommend just using Velcro - too much give and you want the box to be 100% solid.
I use Dual lock to mount the display on top of my monitor, with a little back up tape. It's also got a 1/4x20 tap, but I wanted it as close as possible to the screen.
Hope that helps...