I had a Sinn 103 St Sa back in early 2009, which I flipped to buy a watch I can't recall, which I then in turn flipped to pick up a U1 in the summer of 2009. I never got the 103 out of my mind, and I've been wanting to add one back to the fold ever since I sold the first. I love Sinn chronographs in general, and the 103 specifically has just always resonated with me. As is often the case, though, it was always a case of right-watch-wrong-time for me, and I never made the move to reaquire one.
The U1 was a great camping/water/vacation watch for me, and it never missed a beat. Lately, though, I've just been gravitating towards smaller watches, and have sold off all of my larger divers. When I decided to sell my U1 for this reason, it occurred to me that now was the time to pick up another 103. Besides, I'd been missing a chronograph badly since I sold my Speedy a few weeks ago.
I love the 103 acrylic because it is nearly identical to the classic Sinn 103 of the 80s and 90s (although I'm not sure exactly when Sinn transitioned from the handwound Valjoux 7760 movement to the 7750 in the 103s). The superdomed plastic crystal and anodized bezel are totally killer. This watch was purchased lightly used, but I can't find a mark on the thing. I'm looking forward to adding many of my own marks over the years.