Many people ask so many times which is better and why such company should pick one or the other. before I reveal the story I would like to emphasize being honest the MB cost was hide factor for many businesses but again with Exchange 2010 , now questions comes up what is really left when you take the cost away ??????? Remember Exchange 2010 MB cost is shinning I have seen figures less than 4bucks per mailbox, which is incredible affordable considering the value you get.
From fallowing article, interesting to read Why Serena Software is Going with BPOS, A Customer Story
They [Microsoft] deliver trustworthy, enterprise-class solutions – with the performance, security, privacy, reliability and support we require.
Using Office, SharePoint and Exchange will allow us to collaborate more effectively internally and with customers and partners, many of whom use the same technologies, and we can do so without having to deal with content loss or clients being unable to open or edit a document.
There are alternatives on the market that promise lower costs, but in our experience, this is a fallacy
Oz Casey , Dedeal
MCITP (EMA), MCITP (SA)
MCSE 2003, M+, S+, MCDST
Security+, Project +, Server +