So i'm about 6 weeks into my Sinn ownership experience with a U1 and U2 and I have a few observations, all just IMO of course, having lived with these:
(1.) Just say no to the bracelet.
Looks great in pics, and I love looking at it off the watch on my table, but for me it doesn't fit the character of the watch in person. In photos, the bracelet is the way to go, but in person these are tool watches and the bracelet in person just doesn't fit that role for me. As stated in other threads, it doesn't match the beefiness of the U1 (much less the U2), the clasp is nowhere near where it needs to be and doesn't touch the rubber strap clasp, although it does look great by itself. I'm probably on an island on this one, and maybe it's because the bracelet was a key reason for my interest so I set expectations too high, but it's not for me.
(2.) On the job, U2 > U1
Instinctually if I'm going for a hike, run, swim, or anywhere I need the tooliness, I reach for the U2. I find it much more readable and much more pleasing to use. The other thing I'll add is the feel of the movement (ETA vs Sellita) on the U2 is better ... I don't know exactly why, but it feels more solid and substantial, the Sellita feels a bit more "swatchy" which is ironic! With that said, I'm in no way dinging the sw200, it's keeping great time and works wonderfully, and it's only in direct comparison that you'd even notice or have a preference. Lastly, it doesn't hurt that the U2 looks stunning on a white strap.
(3.) On the wrist, U1 > U2
The U1, if you groove on the retro 60s lego looks, is quite the looker. Of the two, it's the one that gets noticed, and it's the one my wife gave the "oh, in the light, that's actually a very nice looking watch!" She literally has never noticed any other watch I've ever worn. I sometimes catch myself staring at it. It's lighter and more fun, although not as easy to read than the U2. I like my watches tight on the wrist for action and the U1, for my wrist, fits slightly better (let's blame the rubber strap clasp with no micro adjustment).
IN short, the U2 is functionally the one to get, the U1 is fashionably the one to get ... ideally get both!