T.F.
We've been AT&T customers for YEARS...
I loved my old Razor, actually it still works. I keep it charged up and it has all of my old numbers/contacts in it with the SIM card.
When the new Iphone came out, daughter and I got one. We both love them. They don't do well if you drop them and they cannot be on the "warranty" program AT&T offers, however you can purchase a separate extended warranty for about $70 or so. We have had no issues with ours. At this time, daughter's phone has 2 cracks in the screen and we are waiting on it to quit but it has been this way over 6 weeks.
As far as our billing.... Our regular fees per month are around $170. That includes the Iphone charge to each phone of $20/month and the $30/ month unlimited texting, etc.
Hubby has the newest version of Iphone and loves it. Hubby's plan is loaded and runs him about $160/month.
IF either of us were to upgrade or get new phones, we would stick with the newer version of the Iphone. Some people raised eyebrows when we got our 14 yr old an Iphone but we believe in buying the best we can afford at the moment. Her Razor was broken and to set her up on a new phone, etc, we were looking at $200+ so it was justifiable to go ahead and spend the $300+ for the newest, latest and greatest phone.
One huge benefit for me is that when we travel, I no longer have a need to carry my laptop because I have all the access I need via my phone.
We love our Iphones!! Good luck.