Setting asside the legality of not using government-run email for government business (which is a clear violation of the records act), I have one comment:
Ordinarily, there is no way one could argue that a server sitting in somebody's home was more secure than one sitting in a data center owned and managed by a Federal agency. Then the IRS thing happened, showing an incompetency in their IT department that is deserving of much public ridicule and a proverbial "you'll never work in this field again." After that, an AOL or MSN account might be preferable.
30 years in IT, more than 15 of those running ISPs, and I've never seen anything like that level of incompetence from a professional IT organization.
It will be interesting to see if somebody has the balls to issue a warrant for the physical server itself. I doubt it, as this is mostly an excuse for the Repubs to act outraged and make a lot of noise without actually accomplishing anything of value, and the Dems to act like victims and make a lot of noise without actually accomplishing anything of value.
When it's all over, there will be new rules to follow and new hurdles for us plebes to jump over because clearly we need to regulate email or something equally stupid, and as always, the political class will except itself from it's own laws and rules.
Bureaucrats and politicians are nothing if not predictable.