I don't care about GPS or brighter screen. Swimproof is nice but didn't sell me on the S2. What I do care about is battery life and I get 35% more of it with the Series 2 because I don't use GPS (phone is with me) and I set the screen brightness to low. The 38mm really needed the extra juice! Just saying it's the main reason I went with the S2 over the S1.