Man - you brought the dead back to life on this one :-) Most likely apparent from numerous other posts, but in the end I ended up with Network Edition and Zimbra Mobile and haven't looked back. I was happy with the price-performance ration 4 years ago when we did it and it has done nothing but improve and expand since. As an enterprise company, I always get a chuckle when comparing licensing costs with the 4 other companies running Exchange in the enterprise. I was tasked with presenting to the BOD on one occasion as 95% of my data center is now running FOSS. Although Zimbra Network & mobile isn't free, it was the star of the show and there will be converts as a result of the functionality and ease of administration. As for Klug's comments - he was one of the few respondants and did try to help. Look at the entirity and not just a single post. I've also found several of his other posts quite helpful while digging for info on these forums and hope that I have reciprocated in kind to others. As for choosing whether or not to hold out on the paid features of Zimbra - You won't be dissapointed and will most likely avoid 3rd party upgrade/compatibility issues.
8.0.3 UBUNTU10_04 UBUNTU10_04 NETWORK
8.0.3 UBUNTU10_04 UBUNTU10_04 FOSS