Got rid of my pager for my iPhone.
ATT.
Fairly reliable for text and calls.
The biggest issue is the repeat "reminder beep". This can occur, I think, up to 3 times in the native iphone programing. However, if one get a little 3 am beep this will not work. Also, need to be OCD as there is no blinking light as on the old palms and blackberries.
I jailbroke my phone and use a program called intelscreen. This allows repeat beeps for hours and my own set interval. Would not have been happy without this.