I've been using the powered wheelbarrow for about 3 weeks now. Moving gabion rocks up an incline to fill cages. As well as bags of ready mix concrete and fill soil.
The barrow will pull a full load up an incline faster than I can comfortably walk behind it. You still have to lift the load of course but there is no pushing required.
It is very simple to operate, with an on/off switch, a voltage display and a thumb controlled "throttle". There is no pesky electronic brake to fail and lock the wheel in place. The wheel itself is very much an "all terrain" type. It'll make easy work of even the muddiest conditions.
Besides the battery charger, there were no operating instructions included with my unit but it really is pretty obvious.
The throttle takes a little bit of getting used to but once mastered, is quite easy.
A full charge lasts me a couple of days of use.
It is fairly pricey but if you have a sloping block you will find this thing invaluable. You can also opt to buy the kit and fit it to an existing wheelbarrow.
in terms of quality, time will tell, but it looks to be a quality product. I would suggest that you keep the barrow out of rain as the thumb/display and control look like they could be impacted by water damage if left out in the weather.
i'm very happy with my purchase and happy with the service I received.