I have a relatively light duty Hyper-V server running 2 production servers and 3 dev servers. I've been using the RSAT with the Hyper-V role installed, and it seems to do just fine when it comes to managing the server's storage and VMs. I decided to setup a new machine and do some eval on SCVMM. Now that its up and running, I don't see any added value to it compared to RSAT on my Win7 box. Is it just not geared toward a small setup like mine, and really just meant for a much larger VM environment?
EDIT: Besides the ability to to P2V.
SCVMM is targeted at automating operations across many hosts. A single host, or even a handful of hosts, won't be enough to see much difference.
And, by the way, if you're really dealing with only a few VMs, you'll probably get exactly what you want in P2V using disk2VHD. See this:
http://technet.microsoft.com/en-us/sysinternals/ee656415.aspx
Just remember to change the storage driver set to include IDE/ATA before you take turn the disk into a VHD, or it won't boot within Hyper-V.