iPhone is great, BUT, it doesn't seem to always sync well with some email programs as well as other business related applications. Our company has close to 4,000 agents and the ones I've heard having setup problems have always been the iPhone users. Doesn't mean they can't do the job, just setup may be more difficult.
I'm trying to make the same decision as you. It would be the new Galaxy in a heartbeat except I'm not sure about the size. I'm going to have to go into my local Verizon shop and actually pick one up and get a feel for it. The iPhone is also a great unit and I'm one who wouldn't have a problem with the setup, I just think it's overpriced and the fact that you buy it with a certain amount of memory and that's it. You can't add a mini SD card if you need more memory. My biggest complaint about Apple products is they like to reel you in and than your stuck with them right down to the connector cable.
Let us know what you decide on.