Perhaps it is just within my social circles, but this is my observation 99.99% of the time:
The people that I know that use iPhones have no issues with anyone else's choice in phone hardware/software and even support their personal choice and preference... but the people that I know that use Android take every opportunity to evangelize their decision and trash Apple and its products, specifically the iPhone, and point out during they displayed disdain that anyone choosing to use an iPhone must be a clueless tool. It is an odd phenomenon, but prolific IRL.
I was not an early adopter of the iPhone. In fact, it wasn't until years later as the result of a sudden catastrophic hardware failure of my trusty Samsung that I pulled off at the closest AT&T store to purchase a new phone - electing to try an iPhone out. Within 5 minutes, I was back in business... everything that I functionally needed from my office (contacts, calendar, email, etc) was synced via Exchange integration... and it just worked, and continued to work, flawlessly. I use my phone as a critical tool in the process of earning income. I never had the need to seek an alternative to customize things I don't care about, SQA a sea of open apps, play games, etc. Maybe I'm the minority, but I appreciate having zero issues with bugs and or functionality in the several years now I've been using an iPhone. Here's the thing though... I don't care if everyone else uses an Android. I don't care if they never switch. BUT, everyone I know with an Android seems to be very concerned with my obvious lapse in sanity using what I consider to be the most stable, functional, reliable, intuitive phone for business that I've ever used.
Outside of that, I use an iPad as a tablet and I enjoy the cloud sync between the two and centralized management of pics, videos, apps, music (drm and non-drm) for both on one platform (iTunes).
I'm obviously the minority, but I thought I'd throw my two cents in.
That being said, I have a good friend that just went to S4 from 4s and loves it. Bottom line, get what you want that fits your life. IMHO, you can't really go "wrong" these days with either.