Yea the iPhone gps is only tower but unless you are navigating in tue woods, the inaccuracies are negligible. Still good enough for turn by turn.
I like the iPhone. The apps may be fewer but they are, as said, more stable. I have a PC as a primary computer and feel I don't loose anything by not having a Mac. All you have to have is iTunes downloaded and you can access all features. iPhone is just ahead of android. The world goes crazy over a new iPhone or new iOS because it's become the standard that all others try to achieve.
Now for the listed things you want
1) yes get a smartphone, otherwise Internet and facebook are not desirable.
2)either will work and you will probably be loyal to whichever you choose, simply because that's the one you learned on