The Google revolution is clearly here. Everyone talks about cloud. For from US$50 / user / year, Google will provide business grade email. Nexus undertook and extensive evaluation of the Google Enterprise offering and found (there are pages of information in our report) that there is a solution to most requirements, including connectors to CRM systems, hand-helds Blackberry and options for Archive.
Integration to your Microsoft product suite, while not as simple as is made out, is available, well documented and tested.
Nexus doesn’t necessarily buy the "better uptime" argument – we ran a fleet of Exchange servers that had better uptime than Google mail in 2010 – but for simplicity and a fully outsourced mail model, Google mail is a real option.