I would say that if you took any like of phones and asked the same question, you'd get about the same answer. Users with 2 year old phones should upgrade since things are much improved, users with last year's phone maybe not. I think that is just about always the case with modern flagship phones, unless there is some critical new feature on the newest version. That said, I have the S4 and I am getting the S5. I love that they added water resistance, I am looking forward to the faster processor, faster and better camera (if it proves out to be so in real world tests), better screen, improved battery life, etc. There are many improvements that I will appreciate, and since I have a upgrade avail, I will definitely be using it for the S5. I think there are plenty of improvements here and to expect massive "innovation" every year is probably not realistic. My GS4 runs well, I like it. I can't wait for the GS5 now.