I believe this is going to be a handicapped match for Sprint, as iPhone is not just a phone. Steve Jobs and Apple is a strong brand value , backed by At&t's service, they have largest subscriber base. Also the fact that iPhone was sensational hit when it was launched.
Let the battle begin…
1. Technology used: even though both uses 3G technology. Sprint's Instinct uses EV-DO REV-A and iPhone runs on EDGE, technically EV-DO REV-A will have higher bandwidth. It means browsing in Sprint's Instinct will be much faster than iPhone.
2. GPS: Sprint Advertisement shows its very accurate, it can be very helpful while driving as it has turn by turn audio and video driving direction. iPhone lacks the accuracy and feature, but in next model they can bridge the gap.
3. Inbuilt Memory: iPhone as 16GB memory. Instinct 16/2 Max
4. Streaming Radio and Video: Sprint has advantage because of its higher bandwidth via EV-DO Rev-A technology. Also backed by Sprint TV and Radio + 150 more radio stations.
5. Phone as Modem: Sprint do anything for $69.99 is very economical plan, you can attach Instinct into your laptop and surf the web with broadband speed.
6. Price : Speculation: Instinct -less that $200(with discount), iPhone: around $300.
7. Better Network: At&t's "all bars anywhere" is just a marketing gimmick, the present iPhone user can share the pain. Sprint network has improved a lot.