For the last year and half of college I was having a tough time getting announcements for stuff that everyone but me seemed to know about and I seemed to be occasionally missing events and e-mail conversations with groups for certain classes. I wrote it off as me just not paying enough attention to e-mails and notices.
Then I realized right near the end of college that I was actually was missing a significant portion of my e-mails. This was due to the fact that while I normally used the webmail client, one time I had logged into the Exchange client to try it out. Apparently when that happened my e-mail was being randomly grabbed by whichever server was the quickest at that particular moment. Since I never checked the Exchange account I didn't realize until after the fact that it contained hundreds of important e-mails that would have made my college life much easier if I had known about. I'll, I'm probably partially to blame if I missed some warning somewhere during the process that indicated that this could happen.
Still though, I would have much preferred not having to deal with the school's e-mail system so this type of change is definitely for the better in my mind.
Edit: Plus, as others have mentioned, you generally lose access to that e-mail address once you graduate, meaning you need to transition all your contacts to a new account anyways.
In both cases the student needs to figure out how to access a mail system in order to actually use the e-mail address.
If it's already a method of contact between you and the university, why add another place to look by creating a separate inbox?
I'm a college student myself, and while I have an email address with the school, I just have all my mail forwarded from that account (which uses the awful Outlook Web interface and doesn't offer PHP3 or IMAP) to my GMail account. It's considerably more convenient.
Some people will probably disagree with me, but even if more colleges just offered the option to make your account either a full account or simply a forwarding address (as opposed to just forwarding mail from the mailbox, as my account does), it would be worthwhile.
UCF recently had to make this decision and went with Microsoft. And now our students do not have an option of forwarding those messages to an address of their choice.
I remember someone saying that forwarding was turned off so that people would have to use the web interface. I don't know why they would even make than an option.
I think it's highly unlikely that in house solutions will survive much longer. Forwarding or outsourcing to something like Google Apps are better options by far.
Wish more colleges at least gave an option, or did only forwarding as opposed to in-house solutions.
