Joshua, thanks so much for providing your real world experience! Anything else you could add would be greatly appreciated.
Since several companies and multiple models exist I think there must be a number of users out there. (In Europe). Maybe we're get more postings on these from users and any tricks they've employed.
The tongue wheel problem sounds like something $50 given to a welder would solve. (Maybe random wheels on a second jack?) The safety issues are another concern if you're parking and unhooking on a slope which I do and which makes me very nervous every time. I chock and use a X-chock screw stabilizer. I don't think I'd ever try to use any of these powered units on anything but the mildest of slopes. The power caster looks like a cool solution too. I'd looked at their site but was attracted to the wheel mount model because they are out of the way and don't take up storage space.