The Hyper-V MMC is “ok” at best. It lacks a lot of features and polish of SCVMM. I really dislike using Hyper-V without SCVMM, but yes, for initial learning curve, anyone familiar with Microsoft products will have a pretty easy time with Hyper-V. Don’t get me wrong, the GUI is “good enough” I guess for folks running the version of Hyper-V included with Windows 8 Pro and Enterprise, or who don’t have complex enough server environments… but the Hyper-V MMC needs to be dumped and replaced with a lite version of SCVMM that shares the same GUI elements. There is absolutely nothing in common between the Hyper-V MMC and the SCVMM console except for the product being managed. I would not call the Hyper-V MMC a System Center snap in. System Center 2012 does not utilize any MMC consoles, nor does it look like them in any way (which is good, because the System Center GUI is much greater than any MMC snap in). They are separate entities, and in the case of the VM client connection window, SCVMM fails miserably compared to the Hyper-V client connection window. SCVMM can’t even paste to the VM this way.
Delegating Hyper-V to Administrators prior to Server 2012 was a wee complex. It was not obvious. It was in fact, highly annoying. SCVMM at least made that part of Hyper-V ignorable since it took over delegation control. Server 2012 now actually includes a Hyper-V Administrators group, which it frankly needed back in 2008 R1.
So far as inertia, unless VMware makes some major changes to their pricing schemes, it will probably grow quickly. The bottom line in is Microsoft’s favor right now, and that alone can drive decisions. So far as non-Microsoft VM support goes, Microsoft’s does support a lot of distributions by default these days, and the Hyper-V integration drivers are open source under GPL.
Frankly, the biggest failing Hyper-V and SCVMM combined have right now is smart card support to the VM. Microsoft really needs to address this issue directly within both consoles. RDP is not a "good enough" solution to the problem. There are a few industries that this limitation will directly hinder adoption of Hyper-V, and is likely its biggest failing in the 2012 product line.
Smartcard authentication (such as the DoD Common Access Card) has been an option in Windows Server since 2008R2, and has been an option on Windows desktops (a built-in option) since Windows 7 - the problem has been older versions of Windows and non-Windows clients (real OR virtual). The bigger problem is the client support (again, physical or virtual), as in how the credentials present themselves. SCVMM may have addressed this (Server Manger in Server 2012 certainly does, as it actually has settings for smartcard support for client-side authentication) - however, I have no need for SCVMM with a single server - not even for a multirole server.