Later firmwares for the N95? So not the "base form" then?
I had no problems with syncing my iPhone after formatting my computer, or after buying a new computer, as I had backed up my library beforehand...
My iPhone can also access the music on my PC's iTunes library over WiFi. With iOS5, I'll also be able to access all my purchased music remotely via "iCloud", and access my ripped music remotely via (£) "iTunes Match".
Storage - I can put files and documents on Dropbox or Spideroak and access them anywhere using an app, or use Google Docs and access documents via the browser. Or use iCloud once it and iOS5 launch later this month.
You won't get any definitive reasons why it's "the best", because it isn't. You'll get subjective reasons, same as with anything. Ask the same question for "What console?", and some will say "PS3 is the best!" while others say "360 is the best!", ask for various other things and you will get the same.
Some people prefer the iPhone, they will always say "Get an iPhone, it's the best!". Some people hate Apple, and will always say "Get anything other than an iPhone!" (many of these people seem to live at DigitalSpy's forums). Some people prefer the Galaxy S II, or some other top Android phone, and will always say "Get <top Android phone>, it's the best!"