As always in IT "It depends"
Are you running the system for you staff, or to email outsiders? Relevant if you're LM or Boeing or BP. Small companies on one site, not so much.
Do you management think keeping all email (not just their personal ones) private is important?
Will management invest if they find the current system can't do the job?
Are there products and services you can trust to do the job (and afford) that you can buy if the current system can't cut it?
Biting the hand that feeds IT
