Bluetooth vs. Wifi for iPhone data transfer

I'm working on adding sharing support to my iPhone app. Right now, I'm using Bonj开发者_开发百科our to create plain TCP connections over a wifi network. This works great, except that it turns out that many wifi networks in the real world (for example, those at Starbucks and other chains) forbid Bonjour publishing and discovery over their networks.

So that limits the usefulness of sharing, since one of the use cases we imagined was that people could bump into each other where wifi was available and seamlessly share data with each other.

Is Bluetooth a viable alternative for this? We're sending large amounts of data (PNG images) over the wire, so latency and throughput might be one issue.

(I'm also interested in any other ways to make it easy to transfer data between two iPhone apps)