Need to upgrade Asterisk - looking for best solution

We currently use an old version of Asterisk Business Edition for our voicemail system and to manage a handful of phone trees and ACD queues. We use FreePBX as the GUI mgmt tool. We have approx 1200 voicemail boxes. We need to upgrade our system. I’m looking for advice as to next Asterisk / FreePBX platform to move to. I see both AsteriskNOW and FreePBX Distro are now available but do not know if they would work in an enterprise environment. Thank you for your comments.