watch - If I get the less expensive Apple Watch what are the drawbacks?

Maybe this will help with the GPS only vs Cellular models

https://support.apple.com/en-us/HT205547

If you are talking the aluminum vs stainless steel, you have more weight in the stainless steel, but the case and the screen are more scratch resistant (not that they cannot scratch or break, just that it is more difficult).

are you talking about the GPS version instead of the GPS+Cellular version? There are no drawbacks. You will just need the phone with you to make calls on the GPS only version. You can leave your phone at home with the GPS+cellular version. (who would leave their phone at home though?

Solid assist Bob! thanks.