But from a data portability standpoint:
+ Your contacts are easily exportable
- Non-webmail access: exchange-push protocol for smart phones, POP3 (aka Inbox-only), Outlook/OutlookExpress-only access (using, I presume, private APIs).
- If you decide to move your identity off of hotmail, you can't disable spam filtering, which combined with basically POP3-only access means you are forced to login to check you spam folder. At least with Gmail/GoogleApps you can use IMAP to automatically check/sync your spam folder, even though you can't turn off the filtering. The only plus here is that you can dial down the spam filter slightly, which you can't do on Google.
- Since access is POP3 only, the only way to export all of your email is to move all of it into your Inbox and pull it down (or alternate between moving a folder in and pulling it down, then sorting it on the other end back into folders).