A few of my websites went down over the weekend as I moved them over to a new server. I've been saving moving my two primary domains for a while but I had to bite the bullet and move them due to issues involving storage space.
Let me say that I am incredibly happy to have moved my hosting over. Particularly e-mail. I spent several months carefully crafting a fairly intricate e-mail setup with postfix and dovecot. Totally worth the effort. I've eliminated approximately 95% of all incoming spam. The difference is night and day: deluge vs. sprinkle.
Everything is running over SSL/TLS for e-mail. And I'm using SSL/TLS for web administration.
The downside is that I lose all of my ancient website layout for my main website. The site was basically dead anyway so I turned it into a one-page site instead of the ugly mess that it was.