Here's the deal. I've been enjoying using the 680 for the last 10 days or so and it has been a good experience, certainly in comparison to using the Treo Pro anyway. I tend to use it during the week as it suits my needs during the working week better than the iPhone, mainly because since I upgraded Docstogo to v10 I have been using that application a lot more. It really is rather good, syncing files via the desktop software and then working on then on the Treo 680 is easy especially as the 680 keyboard is good to use. I found previous versions of the software couldn't retain the original documents formatting when synced across whereas this has not been a problem at all in version 10. As such, using it now is great and easy.
However, when I get back on a Friday after work I tend to dump it and then use the iPhone instead as the weekends are for playing and the iPhone is a device that suits that mantra a lot better. Plus, it has the wifi option which I can utilise at home whereas at work I have zero access to wifi. At the weekends, I tend to not do work stuff at all therefore there doesn't seem much point in using the 680. During the week the apps I use are mostly of a work nature whereas at the weekend it's all multimedia, browsing and funner things. I think I know that if and when the likes of Docstogo ever comes to the iPhone then that will be it for the 680. It's astonishing that months after the AppStore opened there is still not an application that allows importing, syncing and editing of Microsoft Office documents, this is all the more surprising when you think that Apple are trying to position it as a business device.
It's all the more annoying when you consider how good doing these sort of things would be on the iPhone's lovely big screen. Another thing in favour of the iPhone is that I can use mobileme to keep my desktop calendar in sync whereas to get the same functionality on the 680 I need to sync via Missing Sync for Palm. It's a bit strange though that I am basically using the same two devices that I was using a year ago whilst a whole myriad of supposed contenders have fallen by the gadget wayside since then.
Still, there is no law against swapping out SIM cards between two phones so I can carry on this way i suppose.