This may have changed in the last few years, but another thing I really liked back when I ran Sailfish, was how even the third-party apps would use the standard UI assets and look/function exactly like native apps. That and the fact that they were usually open source and ad-free. For instance one I liked was "Solar System"[1]. Since no sane person would make a Sailfish app in order to get rich, Sailfish apps weren't trying to make money.

[1] https://github.com/zeburon/sailfish-solarsystem