I had and wore out no less than four Nokia 521s... I liked mine so much I bought one for my wife. We used them for nearly two years because they were cheap when we NEEDED a good cheap phone, and later we discovered that they JUST PLAIN WORKED. Unlike most smartphones, which are really small tablets with a phone as an afterthought, the 521 was designed BY A PHONE MANUFACTURER, so everything about it was very clearly a phone FIRST, and an internet gadget second. Nokia seriously knew their shit when it came to making an intuitive UI on a phone.
True, app availability was limited, but WinPhone8/8.1 shipped with a full complement of productivity apps, among which was Nokia's own GPS/Maps app which was faster and easier than Googs; and because the maps were stored locally, it ALWAYS WORKED.
EVERYTHING that came on it just plain worked, the settings were ALL where it just made sense for them to be, and the intuitiveness of their active tiles implementation was something that other phones are JUST NOW approaching 5 years later.
As a result, aside from a few stupid games, I really never MISSED the app store; I happily used my 521s until they simply became too old & slow for the content I wanted to use on the internet. By that time, lack of browser updates was getting me shut out of sites anyways.
Well that, and aging eyes with both of us was making a 6"-ish phone a necessity.
Really, EVERYBODY designing phone UIs RIGHT NOW could learn a SHITLOAD about how to do their craft PROPERLY by living with a Nokia 521 for a week.
mnem