Replaced my iphone 4s with the Galaxy S5 a little over a month ago, other than the learning curve of where everything is, I certainly think this is the better phone. A little big for normal carrying around but more than makes up for it in speed and display.
I went from an Iphone 5 to an s5 and love it.
Quicker and faster on almost everything. I still have all my old apps that I use.
Learning curve takes a bit since I had the iphone setup for years but once you get the hang out it, its easy.
On top of that the battery is lasting longer and is shorter to charge.
I like mine. Lots of battery life, super-quick charging, and so far no burps, crashes, glitches, etc.
I've also noticed that it seems to get better reception (on Verizon) than other phones that are in the same location. I was recently in Hancock County, TN (boonies) and could get 4G when others got 3G, or nothing at all.
Mine has been good, pretty impressed with the camera too. Stronger signal than my old galaxy nexus both in WiFi and cell. Minor annoyance was the keyboard but I downloaded a new one and also changed to nova launcher. Speaker volume is great, call quality is great, screen is great, being dust proof and waterproof to 3 feet is good since I don't use a protective case.