EA4500 is a Smart Wi-Fi App Enabled router. New web/cloud based mgmt coming out this summer. Current software that it comes with installs on PC. Best router I ever had. Also, I just installed the new Linksys powerline kit PLWK400 with wi-fi to get better wi-fi signal in backyard. Works great.
Excellent link - thank you. I've got a 4200 and am having bad latency issues and also poor wireless distribution in our home. Was hoping this might be a fix, but it says same hardware, so no sense in 'upgrading' in my case. Again, thanks for that link!
I've read on the web they are identical in terms of hardware, it is just a packaging change. Depending on when you purchased it, the EA4500 may come in-box with newer firmware, but both both can be update the the latest supported firmware. (Including Cisco Connect Cloud, if you want to take advantage of that functionality.)
The difference is the processor and software. they are both the same thing, the software on e4500 is older and also its processor but it is the same speed as the e4200, the e4200 is just a more optimized version of e4500.