Re: From the other side of the fence...
I don't agree that a replacement to exchange/outlook has to be better or even implement the full featureset in outlook. My post above notes that it has to "let them do their job"; eg; it must be "Task adequate". Task adequate doesn't have to be "outstanding", it means "must implement the minimum features required to do the job".
You could totally leave out the notes and tasks section of outlook and not many people would notice, and the contacts part is implemented in most half decent mail programs already. Quite frankly, I think that most businesses could get by with what I have mentioned above, simple delegation for the emails and the calendar.