The overall design of the iPhone does seem outdated, however; I had the Samsung Galaxy S3 and it was only nice for two things - larger display and less OS restrictions. Aside from that, it was crap. I've had my iPhone 5 for weeks and it's working great. The Samsung was laggy and didn't always work as advertised. A major downfall on the SIII was the default keyboard. It was useless and you had to install a third party app (Swiftkey) which took about 30 MBs of RAM to run, in turn leaving the user with a lag issue.
Other features, such as driving mode that spoke texts was great but only worked about 50% of the time. S-Voice was worthless although Google Now took care of that. The gesture features never worked right, the browser crashed or locked up after maybe an hour of browsing, and the screen cracked so easily. I've been browsing the net on this phone for nearly 3 hours at work and things are smooth.
Do I miss the larger screen? Yes but it was also inconvenient at times. Was it nice having more control over setting and shortcuts to WiFi on the notification bar? Sure. Apple can put those in iOS anytime, they're just lazy. Widgets? I noticed most android widgets eat battery like no other so I never used them.
I suspect the S4 will be the same as the S3. Full of great looking features you'll never use. All this crap really is gimmicky. The focus should be on features people want with motivation to make them work. I'm new to iOS and Apple. I'm a long time Windows and android user (and Linux). The issue I have with android and their associated manufacturers (Samsung, Motorola) is that they introduce stuff that doesn't work or hardly works then abandon it or leave it broken. Fix things and support your devices! It just seems like bugs are left to hang out while new junk is introduced. The SIII had a garbage keyboard and Samsung knew it but left people to swim with third party apps. Stupid.
I expect more of the same from Samsung, so long story short, yes the iPhone does seem dated but it works fine for email, texting, and browsing. Like the temp sensors in the S4. Temp sensors on those handheld weather devices are inaccurate so I'm sure the S4 will be too, but users won't care because it's a "feature".