As a counter point, I'm still using my first gen (not even Series 1!) Apple Watch after 2 years and it runs well enough for my uses. I would likely use Siri more if it was more responsive, but I use the notifications, Now Playing view, activity tracking and more all the time and it is really nice.
"runs well enough" for a device that is barely two years old and several hundred dollars, already obsoleted by the manufacturer, is hardly a ringing endorsement.
Fair enough, though I wouldn't say it's obsoleted. I can still run the latest WatchOS and that's true of the forthcoming WatchOS as well.
I didn't feel compelled to get a Series 2 watch and unless there's something dramatic in this fall's hardware, I'm not planning to upgrade to the next one either. I'm happy with what the watch does.
The Series 1 is the original Apple Watch but with the processor from the Series 2. It's a different device because of that, and lots of us call the original a Series 0. However, go on Gumtree and you'll see plenty of peppy claiming they're selling a Series 1 when it's actually an Original Apple Watch.
To make matters worse, the SoC in the original Apple Watch is called the S1, and the chip in the Series 1 and Series 2 Apple Watches is called the S2, making the numbering more confusing and preventing us from shortening anything to S1/S2.
The good news is that Apple Watch appears to hold its value like other Apple products. I just spotted a recent one on eBay that's exactly the same as mine which sold for $135.