Ever since upgrading to Mountain Lion, I noticed Mail often freezes up for a good 5-10 seconds at a time in the middle of typing. This happens constantly, and every time I notice it says "Saving Message". Unfortunately, it chooses to do this every time I start typing, and I often stop typing when I don't see the text appearing, so it takes me forever to compose a message of decent length. How do I fix this?
Apparently this has to do with the draft email being saved to server. As a workaround, try disabling "Store draft messages on the server" in Mail.app Accounts settings.