We can easily search for all of our emails by domain or email address in one place! The interface is also very intuitive which makes it easy as well when I am searching through my archive looking back at previous messages that were sent out from an old project/email account etc..
It's not super customizable but you get what ya' pay fer so if this fits your needs then great!! If there was more customization available such as creating custom fields (eg date created & last modified) we would have been able solve some issues easier than doing multiple searches using various filters like "Subject:".