To be honest I got my 1st iPhone as a fashion statement and I hated it until I got used to it.
Battery life is fine, I charge it once a day.
I now find it hard to use any other phone, I really fancied a Sony experia and when I eventually bought one it lasted 1 day then I got rid of it due to the screen looking horrible and not being able to use it properly.
My girlfriend has a blackberry and I have had a go of that and find it annoying so I wouldn't use another phone as like you said I'm now accustomed to it.
Being fair though I have to admit I've never had or entertained a HTC or any android/windows phones.
Mattlfc is the man to ask advice