Research In Motion - RIM
As a business tool it'll be great, but speaking from experience and administering them daily/owning several. They're still not hot on UI, not as bad as Win Mobile but still not as user orientated at the iPhone.
I'd suggest holding out on it until they've laid down a clear roadmap, they're still learning how to satisfy Joe Bloggs. We'll be getting some at work for testing shortly...
In summary, would I own one personally out of choice? Hell no.