I still use mine daily, albeit as one of my multiple phones
(N900 [in bag, mainly ssh], Droid4 Android [in Pocket, Signal + Browsing + Hotspot] and Nokia 808 Pureview [in bag, Pictures])

Besides my Droid 4 its my main phone. Browsing is nearly impossible due to missing SSL. A good 70% of bigger sites will not be accessible. Another 10% cannot be handled by the stock browser, but only by Opera.

Using it for calling, sms, navigation, reading, stargazing, music and videos is still very much possible. The Galaxy of Fire Game it came with is awesome.

My main uses for it are:

• Reading: its OLED screen and low weight are awesome for that.
• Navigation: Offline maps are awesome, responsive and do not drain the battery, but last update was 2015 so problems are starting to arise.
• Watching TV shows: Converting them on PC and enjoying on the OLED screen.
• Public Transport: Fahrplan is still a big joy to use, thank you smurfy!
• Mail: N900 has dead modem, so N9 it is, no way Android gets access to my mail.
• Alarm Clock, FM Radio, Music, Stellarium

Would browser, SSL and maps be up to date it would still be my main phone. But because of these things I can't recommend it anymore, even though I still love it.

They are sometimes on Aliexpress for 30€.