I am in love with this phone!!!
I came from the Droid RAZR MAXX, which I thought was a great phone, but I learned on the first day that issues I was having with the DRM were with the phone and not my imagination.
Whenever I would write texts on the DRM, every word would be misspelled. I thought I was fat fingering, but that was not the case. While in the store, every word was coming up correct. My Bluetooth connections were spotty. and frustrating, sometimes in the car, I would get half-way to my destination before I would get a connection. With the s4 connections are instantaneous, and hand-offs between BT devices is awesome.
There are few quirks, but I'm working through them, and I still find some new feature every day. In fact I thought it was funny that I was browsing Amazon the other day and saw an item for NFC tags. Immediately the light bulb went off in my head and I remembered that I had NFC on the phone!
I really couldn't afford it, but I am so glad I got it!