I am always a fan of Exchange server, it's a great product specially Exchange 2010. But recently how Microsoft started treating Exchange, really disappoints me. Exchange 2013 is another Vista! Microsoft, please stop doing experiments with your flagship products! Your recent approach towards on premises Exchange has already shaken the morale of your loyal customer base. Please listen to your customers and give them what they want and not what you think they should get. Look at the whole messaging eco system, you radical changes, no clear product road map in place is making other 3rd party product developers crazy and the end user is always at the receiving end.
As far as the Office 365 is concerned, it's a total mess. One service outage after another. Once of my clients recently lost a larger volume of mails due to one of such recent outages and most funny thing, if you call the support, you will get a response, "We can't recover those mail." Come on, Microsoft! Are you using your Office 365 platform for bug tests with customer’s data at stake? Most of the time, they deploy some patches the back end without any prior intimation and when it breaks something, it takes another couple of days to fix it and in the meantime, you are left with only praying and hope someday it will be fixed.
Microsoft, you can't sails two boats together, decide, either you going to remain as a product company and deliver some of the finest products like past days or be a support company and drive everyone crazy with solutions like Office 365. I am a diehard fan of Exchange and can't see this product tearing apart due to mismanagement.