Hi Troy,
I prefer Text email.
Lynn is right about the open rate but Henrik pointed out the problem with it.
I'm using text email because nowadays most of the email software (no
matter web-base or software-base) are smart enough to detect the HTML
links.
In this case, we don't need to care much about the links. Readers will be
able to read the click on it.
However, for those products which need to present the images nicely
to the readers, the HTML emails would be more suitable.
And text is easier to control compare to HTML which different software
interpret HTML codes differently. (Just look at how Firefox and IE works)
And do you know that if my email can't read HTML file, it will become an
attachment that require me to click on the attachment, which opens
another window to read the HTML message.
This make me worried if it carried virus !
Just my idea.