I've learned to first raise my wrist and THEN look at it - but that upsets my running rhythm. Perhaps the biggest drawback of the series 0 may be the noticeable lag before it displays the stats while you're running. Functionally, the difference is in speed and whether or not you need to carry an iPhone and, you can swim with it (although even the Series 0 is not bothered by rain). Stats recorded on my run yesterday while carrying my iPhone in my back pocket and wearing my Series 0:

But if you have a phone with you, you could simply use its altimeter - Which means even a Series 0 would work as well. I would argue cellular is less essential for hikers, because they are probably bringing a pack with them and the 'bulk' of a phone isn't a problem. The barometric altimeter is in both Series 3 with and without cellular. The altimeter and the cell ping matter, especially for fast walks. Hikers should be in the same category as runners/bikers.

Series 1 does not have GPS which is a feature of all Series 3 AWs. Series 3 is faster than Series 1 (or 2). Series 2/3 AWs have brighter screens than the Series 1. The Series 2/3 have better waterproofing allowing for water activities while wearing the AW. The speaker and microphone on the Series 2/3 are better than the Series 1. Other reasons to pick the Series 3 over the Series 1 This would also apply buyers of the Series 3. I have a stainless steel Series 2 AW and the sapphire crystal was one of the reasons I got it over the Series 1. Definitely should be a consideration for those prone to hitting things. The higher end models have a sapphire crystal face. From a technical perspective, there is nothing unique Simply put, these options are a personal decision based on budget and fashion. Internally, they are the same as the $399 Apple Watch Series 3 with cellular. On the high end, the stainless steel, Hermes and ceramic Edition Apple Watches come with cellular connectivity.

Apple watch series 3 gps vs series 1