Exchange doesn’t even know what the definition of competition is in today’s enterprise environment! Ok, calm down you Gmail fanatics! 
See this post from Mohamed Baher (an MCS engineer):
I’m happy to announce Microsoft’s strong position in Gartner’s 2010 MarketScope for E-Mail Systems report, in which Microsoft is the only vendor given the top rating of “Strong Positive”. Microsoft is uniquely positioned to deliver e-mail and calendaring technology to customers in the way that makes most sense to them – on-premise, in the cloud, or a combination of both. See the full report at http://www.gartner.com/technology/media-products/reprints/microsoft/vol10/article19b/article19b.html
From the report itself:
Microsoft released the fifth version of Exchange in November 2009. Exchange 2010, which is starting to increase its market penetration, promises improvements in storage efficiencies, high availability and disaster recovery, as well as more granular administration control and user self-service options. We expect adoption to follow the normal trajectory of previous Exchange releases, peaking at 50% by the end of 2012. The real action, however, is around Microsoft’s Exchange Online service, a subset of the large Business Productivity Online Standard Suite (BPOS) cloud collaboration offering. Throughout 2009 Microsoft added features to the service, and, more importantly, cut the price in half (to $5 per user per month), while quintupling the storage (to 25GB per user) — bringing it close to price and storage parity with Google GAPE. In November 2009, Microsoft said it had 1 million BPOS subscribers. We suspect that number has since doubled.
In 2H10 Microsoft will release the first service pack for Exchange 2010, with an emphasis on archiving, mobility, browser access, resiliency and management services. In 1H11 it will update Exchange Online with the 2010 version of Exchange, which is better suited to working in a multitenant environment. The current 2007 cloud release lacks some essential features, such as password synchronization, a health and performance console, multimailbox search and end-user password resetting. Furthermore, simple e-mail administration requests, such as to track a message, forward mail to an external mail box and disable ActiveSync require submission of a service request to the Exchange Online help desk, which creates operational inefficiencies for customers. Nonetheless, Microsoft continues to prosper in the e-mail market with both its on-premises and cloud options. Longer term, we will see the introduction of numerous hybrid e-mail models from Microsoft, with some mail boxes live in the cloud and others live on-premises. Google has emerged as its closest e-mail competitor, and it will remain so for the next few years.
Rating: Strong Positive
Mike Crowley's Whiteboard 
Thanks for the post, I’ll keep checking back for more stuff, bookmarked!