XMC-1 will probably not be out until late July possibly August when I spoke to the Dan at the Emotiva Road Show in Naperville, there is no announced date as of yet as they want to make sure the launch goes as smooth as possible.
Marantz - AV7005 is the older model, newer is AV7701 - Two of the main differences are 4k Pass Through / Audessy XT32 (Big Upgrade)
Emotiva UMC-200 - XLR(sub only) and only HDMI video inputs if that's an issue (I am looking at this unit for my bedroom)
McIntosh MHT-200 - No HDMI or 3D support if I am not mistaken. I understand you want to move to McIntosh, but I would wait until you get the unit you want.
How big is your Home Theater Room? That may have an impact on which way to go as well.
I will wait for AcuDefTechGuy to tell you to go with Denon and ATI