Blackberry 9360 or iphone 3G?

Ok so I have a blacberry 9360 and I do love my phone but there always to be something wrong like now my battery is really dodgy because when I'm on the net my phone says battery is low shutting handheld down and my battery is half full its so weird, so I have to have the charger left charging it even though it says full. I know its the battery not the phone but all my friends are coming off blackbery going on iphones and to be honest even though its just my best friend who's keeping his blackberry I won't be able to talk to all my mates accept him and iphone seems so good like everyone says how good they are. But my dad says we can swap phones because he said he's getting old now and he don't mind just having a normal phone like mine. His phone is in pretty good condition and yeah its an old iphone because its 3G, I feel abit guilty because I do love this phone but its annoying me now and I'm not sure what my mum will say or what I should say I feel so ungrateful but I've always told her how much I loved and apreciated this phone before I was even interested in iphones, but mum said that iphones were meant to be the best phones so surely she should be ok right. I dunno am I making a right decision? I do want my dads iphone. And will his sim card work in my phone?

Iphone