Using Shark007 as well and Developing MP under Parallels. Of couse you need to select the proper codecs and know what you are doing.
MP under Parallels runs smooth but not as smooth as a real Win system. But that applies to all applications. Also it has some annoying bugs in its hardware DirectX9 support.
Of couse you need a powerful Machine to have Virtualization run smooth in general. Using a Core i7 iMac myself with 16GB of memory (will upgrade to 32 soon - have too much stuff open at the same time in my three screens and too many different VMs).