I would probably start looking at the Samsung B7330. I have not had the chance yet to try it out myself, but the specs are quite good and it's a device I would even consider for myself.

You said that your company have used the Treo which of course runs on WM Pro, which means there are bound to be some usability issues (e.g. not being able to do everything without touching the screen). As the Samsung runs WM Standard you won't have that problem at least, and WM Standard is in my experience noticeably snappier than WM Pro (excluding the HD2, of course!).

You said people complained (rightfully so in my opinion) about the confusing menus on S60. WM Standard's menus are much simpler in comparison, plus they are index based which means that they are much quicker to navigate: every option is always just one click away – once you learn the indexes of commonly used operations you literally fly through the menus. With the B7330 you also get a 320×320 screen that you had on your Treos.
The downside with WM Standard is that you won't be able sync notes natively, though there are 3rd party solutions.

Along similar lines you have the HTC Snap, though it's a little low on memory (both ROM and RAM), but depending on how you use it it might not be an issue for you. The general consensus though seems to be that it's slightly faster than the Samsung overall (I have not been able to confirm this myself). Its “Inner Circle” function is aimed precisely at corporate users which you might find useful (though again it depends on your usage).

On the WM Pro side I think there are very few options right now for corporate users, with the Touch Pro being the only alternative. If you don't mind sliders (I do) then by all means.

But I think that in the end you have to be aware of that you *will* have to make some compromises, you will not find a device that covers each and every need you may have and that all the employees will love. Once you accept that, and you define what features are essential or important to your company and employees, you will be well on your way to make a decision, as that will allow you to discard many platforms/devices.

Good luck!

As for the E63, I preferred the E71 mostly because of the build and the few extra features. As I said, the E71 is not perfect, but it's the best one.

If you are concerned with user's actually knowing about their device, this would be the best route, as it would leave basic support in their hands, and then the implementation of a mobile device policy would ensure that corporate information on said device is up to specs.

If users choose not to bring their own device, then your offerings need to sit on the Nokia and WinMobile sides of things for device and admin consistency (speaking Exchange only).

Dumb-phone wise the options are great… problem is all our users have 'smartphone' requirements.