I recommend moving to the high-end email packages and the newest versions. Control, management, flexibility, power. You want the tools that can take your use of email to the highest level. It will be easier to use encryption and take advantage of security features. Some packages even allow you to scan for inappropriate content.
Email is a completely different experience with the high-end tools.
As your volume of email increases, you'll appreciate having the extra power. Make it Easy to Email You. As you become a highly effective emailer, you'll want to funnel more and more of your communication into your email system. In other words, you want to make it easy for people to email you. This is, however, a tricky balancing act.