I would imagine it would be significantly faster, and you must be doing some processing to extract the email body.
I'll run some tests (when I can be bothered!) and post the results ;) Not sure exactly how accurate they'll be though, cos the IMAP routines won't let you retrieve just the whole message, which is what I wanted to do!
The fun is going to the pub earlier because you haven't got as much code to write, nor as many gotchas to resolve since someone (me) has written the code for you.
If this was a commercial venture and I was doing it as a job, I'd concur. As it is, I'm writing code 'cos I enjoy it, so getting to finish it quicker isn't really an issue, whereas knowing you've done something yourself is an issue, for me at least.