I downloaded an eval of Exchange 2003 from Microsoft recently. It was a three month eval.
I had to decide the other day to either stop using it, or part with about $2,500.
My decision? Stop using it.
I didn't really hate the software. I had to spend ages getting it to do what I wanted, and in the end couldn't quite get it to anyway. (I wanted it to aggregate POP3 accounts for me, and I had to stuff around with third-party plugins, etc). In the end I left my e-mail client be the POP3 client for all my account and just use exchange as the message store. This was cool, because it gave me most of what I wanted, that being a centralised store for all my e-mail messages that could be backed up on a schedule.
I had trouble getting my address lists to work the way I wanted in Outlook (it wasn't honouring my address book) but I wasn't too worried about figuring out how to bend it to my will (not worth the perceived effort).
I was glad that I'd battled with it though, as I learned a fair bit about administering the product, which proved helpful given that a client is also rolling out exchange at the moment and I knew a little bit about some of the challenges they were having.
But I'm not parting with $2,500 just so that I can backup my e-mail every night. I've gone back to my .pst files, and I just have to close Outlook and do an 'xcopy' backup. 20 seconds worth of scripted effort vs $2,500? It was still a hard decision, if I was Bill Gates, I'd be using Exchange.