This is a horrible decision, most clients do not want, or cannot use the "cloud" due to cost or regulatory requirements which is really just an overhyped code word for hosting an exchange server in a data center which you have no control over who knows where.
Many organizations are much more comfortable running everything in-house and being able to directly work on fixing problems rather than being one of several hundred thousand/millions of customers that a hosted vendor really could care less about.
Typically i could sign on to a server via RDP and fix an exchange problem in 15 minutes or less where it has taken hours to get a response out of Office 365 support.
E-mail is too crticical of a business tool for businesses to outsource.
Office 365 and Cloud hosted email in general (including Google Apps) is OK if you don't care that you can call someone and have a problem fixed quickly rather than submitting a ticket and waiting who knows how long until an issue gets resolved.
Also if you don't care that you can't email anyone internally if the internet goes down.
Sadly after pushing Microsoft products to our small business customers essentially since the days of windows NT 4, we are going to switch people over to Linux unless they need to run a windows based server-side application.
There is very little benefit for SBS Essentials if you do not want office 365 vs running Linux, Samba and one of the variety of Microsoft Exchange alternatives that are readily available which do support ActiveSync and Outlook connectivity.
In case Microsoft has not been paying attention, many small businesses are hurting for cash flow and now is not the time to try to squeeze 2-3x the cost out of them, most of them just can't afford it, especially if you have 30-75 exchange users. Even at just 40 users, office 365 with the cheapest exchange online plan would cost almost $20,000 over the typical lifespan of a SBS, and you still need to buy Standard windows server 2012 and CALs internally anyway on top of that.
If Microsoft's goal by discontinuing SBS is to lose a signifigant share of the SBS market they're likely well on their way to meeting their goal.