I don't disagree with anything Jason said, but I'll add the following ideas as a holdout Outlook/Exchange-phobe in my university:

1. How does the company rely on Outlook/Exchange? Where I'm at, as best I can tell, it's primarily used for email. No task delegation, no assumption of being able to see everyone's calendar or free/busy time, etc. There are exceptions to that, of course. My recollection is that department heads in my college pretty much had to use calendaring so that the Dean's office could figure out when to set meeting times.

2. Following on with 1, what's the least amount of stuff you have to publish via Outlook/Exchange to not irritate your coworkers, or for them to not notice you're not putting 100% of your work life into Outlook? Free/busy availability? Delegating tasks? Do you even have to put your timed reminders into it, assuming you have some other working system that doesn't violate records retention policies or some other regulation?

For me, at least, I can divorce myself from Outlook/Exchange entirely. My boss knows he can email me and I'll read it. He doesn't care how I read it, as long as I can do what I need to (it's forwarded to a Linux mail server I run as part of our lab infrastructure, and I use primarily Thunderbird from the work Windows laptop). Both he and the office staff (and half the college, it seems) has my cell number for more urgent stuff. Nobody has ever tried to sign me up for a meeting via Exchange; they'll call me, email, or ask in person. I've got as good a record-keeping system as any of my coworkers ("When did we last go to that jobsite?" *search DateBk6* "April 11-12".)