Yes, I like to consider myself mobile OS agnostic in that I believe in using all of the major phone operating systems (iOS and Android mainly these days, some WP10 just so I can complain about it). Up until this year, I have had only two smartwatches including the original MotoActiv and the Sony SmartWatch 2. After having a smartwatch very early in the game, I realized I needed to take a break and wait for the 3rd and 4th gen of watches to arrive. Well, after doing the Android watches, let's see how Apple does theirs.
This watch is still the best hardware I've seen on a smartwatch and it does really feel more like a watch than a smart watch. I chose the 38mm size since most smartwatches I've owned up until now have been WAY too big and just look a bit funny on my little wrists.
One of the biggest reasons why I went with an Apple Watch Sport was the HR features. I was considering a fitness tracker but after looking at those with heart rate (HR) sensors and seeing their costs realized that I'd be better off just getting an Apple Watch and get more than just fitness/health tracking but glance-able notifications.
Getting used to using the WatchOS 2 is a bit of a learning curve since it operates unlike any Apple product. It's UI is so drastically different than iOS that you wouldn't even think it was an Apple GUI besides it's usual Apple 'prettiness'. Navigating and understanding what Glances and Complications are is a bit hard to grasp initially but once you see how they work on the Watch they become much more obvious.
Overall so far I like the fitness features and notifications the most, like all of my previous smartwatches. I did get a new band that was affordable and looks great (ie not an Apple band but one on amazon).
Some more screenshots from the Apple Watch OS2