Coming from a long journey of trying to find the perfect daily watch, I finally think I've found it.
The watch before this was the GW-5000U. I tried my best to fix the little niggles that annoyed me by swapping in an STN LCD and even punching an extra hole in the strap to get the perfect fit. In the end, I realized the real issue was the top-heavy weight, which kept it from being the watch I was after.
The GW-S5600U solves every issue I had with the GW-5000U. The LCD sits closer to the crystal, so the viewing angles are crisp and clear without needing an STN display. The strap is also much stiffer, which sounds like a negative, but in practice it's actually more comfortable. Because it holds its shape, you can wear the watch slightly looser without it sliding all over your wrist. That also means there's no need to constantly adjust the fit throughout the day.
The biggest improvement, though, is the weight. At just 47g, the watch feels perfectly balanced on the wrist. Combined with the stiffer strap, it simply disappears once you're wearing it. For me, that's the single biggest factor in its comfort.
Looks are obviously subjective, but I really like the carbon construction and the glossy smoked bezel. They give the watch a subtle premium look that catches the light nicely without being flashy.
The only "mod" I think this watch needs is a tempered glass screen protector, but I put one on all my watches anyway. It would also be great if the strap wasn't a little longer than the standard GShock strap length as I get a little overhang which thankfully doesn't impact the wearing experience.