I had an iPhone 3g years ago, and a couple of cheapy Android phones, and still have a Galaxy Tab tablet.
The iPhone was a terrible phone, both for the fact that calling anyone was painful and Poland's data plans at that time were very harshly priced. It also had the 'amusing' feature that, as I had the phone set to English language but was living in Warsaw, whenever anyone called me from a Warsaw number it would display (221)234-567 (22 is Warsaw's area code, for everyone else).
The Android phones seemed to require so much work, As they were cheap they were left behind quite quickly so I seemed to be constantly finding unofficial updates, and apps to add the functionality missing from them.
Then I bought a 520 and everything just fell into place. While the app store is relatively quiet, the OS itself does so much more and I found myself using it as a helpful device more and more. It uploaded any pictures I had taken with my PC as soon as I walked through the door, my partner and I had calendars that we could compare and join, allowing appointments to be made from either my phone, hers, or the PC and instantly synced between all of them. It included (some added later through updates) great features like the Swype-like keyboard, usable everywhere, Internet sharing, a screen that you could use with gloves on, and can be turned on by tapping as well as by the button, multiple live tiles for different email accounts. It also comes with Here maps, which can be downloaded for offline viewing/navigating.
In a way this possibly hurts the store as the built in defaults are so good. Currently I only have a few apps installed: for my bank, phone network, an OBDII scanner, and a PDF reader.
There were many more, and some of them might seem unimportant, but I suppose the shortest way I could sum the phone up was that it made me happy far more often than it frustrated me, and needed almost zero configuration. Unless Windows 10 removes all that (and Family Room has already been axed, sadly) it will continue to be solid.