Do you use Verizon? If so yes Do you have 4G in your area and your phone could use more speed, if so yes? Is screen size a issue, If so yes? If none of these things matter, No. I'm very happy with my i5 because on Verizon my i4S could not do data and voice simultaneously, it was a pain because im a HVAC tech and need to surf the web and talk or send pictures/Emails/weblinks and talk but couldn't, so it was a no brainier for me.
So how did you do voice and data together? Everything I've read says that you can't on Verizon.