I was using the OSS edition for a long time (about 1.5 years) and then upgraded to the Network Edition about 8 months ago and have been gradually getting existing customers onto the NE (all new customers go to new system).
The situation with a possible MS buyout of Yahoo has me very concerned. If this were to happen I'd expect Zimbra to be quickly killed. I'm wondering if it's possible to convert from the NE back to the OSS edition. I know I'd be giving up Outlook connectivity and backups and probably a few more features. But the thought of having my customers stranded in an unsupports and unscalable product is a bigger concern.