I would like to hear more about your impressions of the Ural and the K75.
Things I liked about the K75/Hannigan:
The handling was spectacular and the bike pulled the sidecar very well. I didn't have wrestle it at all, and I could take it on the highway quite comfortably. I could carry things in the trunk and they stayed dry. There was more space for the passenger and the venting was nice.
Things I didn't like about the K75/Hannigan:
The bike's age was palpable. It was beat up and needed a lot of things, and I just didn't like it enough to put the work into it. It didn't fit me very well and the parts I needed were either unobtanium or priced as if they were. I didn't like being the passenger in the sidecar, because the sidecar seat was so low that I might as well have been sitting on the ground with my legs out front of me. There was nothing to brace my feet on to not have my knees hyperextended. I also felt more isolated from the driver (and from everything else) in there. It would be safer to carry kids in there since there was so little opening for them to stick any body parts out, but you might as well install a portable dvd player, so they won't get bored in their isolated pod. And the sidecar wall was too high, hard to climb in and out, especially without the convenient step bumper/door setup that the Ural has.
Things I like about the Ural:
The person in the sidecar is more connected to the world outside. Rider and passenger can look at each other and yell to each other more easily. And the seat is placed high enough that my knees are bent when I ride in it. It is popular everywhere I go; I have met a ton of people I'd never have met without it, including my husband.

The bike is reasonably comfortable and I was able to easily buy an aftermarket tank shifter when I needed it. It's fun to ride it in the snow, and with all that weight and steel I don't worry about banging it up on terrible surfaces. You can fix it with basic tools and you don't have to be a mechanical genius.
Things I don't like about the Ural:
It's slow. Top speed 62mph, flat out. The carbs need to be rejetted differently for winter vs summer. The bike vibrates parts off all the time and from all reports I should not expect to put high miles on it without lots of garage time. The handling is terrible enough that I wouldn't want to go more than that top speed of 62mph anyway, because it would just be too scary. I have adjusted it like crazy and I still have to muscle the bars pretty much every minute. It pulls right under acceleration and left when you roll off, and every gearshift brings a little jerk to one side or the other. I had to take the windshield off the car because the angle made it hard for the physically challenged (me, and others) to climb in and out. The tub opening is just short enough that it's hard for me to fold my very long legs to get myself out of it.
Things that are just things: I have been letting my friends ride the Ural. Pretty much anyone who wants to, I take them someplace with no traffic, trade seats, and let 'em have a shot. The handling quirks are right up front; you aren't going to get it up to school zone speed without realizing it's a crazed monster, and with all that weight you're not going to fly the car by accident. One of my friends put it in the ditch, and I just traded seats with him and drove it out, no harm no foul. I was much more hesitant to let people ride the K75/Hannigan outfit, because it was so well sorted you could easily get up to dangerous speed before you got a proper sidecar scare. And there is always a sidecar scare. If you're gonna drive a sidecar you have to learn about them. I have been calling the Ural the big crayon of sidecar bikes. No precision, but it forgives the hamfisted, if only because it slows them down while they learn to cope.
I expect the Super10/DMC outfit will be like the K75/Hannigan in that regard, and I'll need to be much more careful about letting people try it. They're promising me that level of handling. I already know the Super10 fits me and is in perfect condition; I won't be looking at a lot of work to redeem a roach beater of a motorcycle. The shape of the car I am getting is similar to the Ural's, with the convenient step I like, but it is larger in every dimension. So it should be easier to climb in and out, than either the Ural or the K75/Hannigan, and hopefully feel as sociable as the Ural, rather than isolating the passenger. It will weigh less than the Ural, though, because the tub is fiberglass instead of steel. The windshield can be folded all the way forward for the passenger climbing in and out, and all the way back and down when there is no passenger. Having the windshield will make it nicer for the passenger, especially at speed. The trunk is not going to fill with water in every little rain.
Right now I am planning to keep the Ural. It is its own thing and it's fun. I'll ride it in the snow every winter.

But I am hoping the new outfit will bring me back some real traveling range, so I can get out motorcycle touring again.