What's the difference between the new watches?

[iMore Question]

My kid wants an Apple Watch for Christmas and we're probably going to get him one but looking around, there are several versions. What are the differences? Some are cheaper, some are more expensive and what's the latest and how much is that going to cost me?

 

[TripleOne]

Hello!
Apple is currently selling the Series 1, Series 3 GPS, and Series 3 GPS + Cellular.
The Series 1 is last year’s model, it is 50% faster than the Original Apple Watch.
The Series 3 GPS is 70% faster than Series 1 & Series 2. There is a built in GPS, which is very useful for fitness purposes. The Series 3 GPS + LTE offers the same features as the GPS version, but it has the ability to connect to LTE.