Spigen Slim Case. I have always liked Spigen, having a handful of their cases for my phone and iPad. They are never my favorite, but always solid design, quality materials and their slim line is usually moe "basic" and solid than other brands, in a good way.
Their slim Apple Watch case is very much in line with the ethos, and theres not the really else like it on the market. I like it a lot. It gives the watch barely any bulk but has good protection from random knocks. I dont use a screen protector, so this is not 100% safe from damage, but it helps with most bumps and dings for sure.
Many people will not like the embossed logo on the bottom. I actually like it, and think it is a cool addition to the design, which would otherwise be a little basic. But I like cool looking branding personally. I suspect most people do, but not most product aficionados.