This may or may not help, but ex. mutt lets you read HTML mail by running it through lynx/elinks/w3m [0], and I've had great success with this in a mostly-Outlook environment. I expect you could do the same thing with other clients.
Every guide I've read recommends using imapsync and msmtp for sending.
http://stevelosh.com/blog/2012/10/the-homely-mutt/#getting-e...