Not surprisingly the MacBook pro won hands down. All systems were reading and writing to my NAS storage via NFS or Samba. The Macbook Pro core i7 incidentally was connected via Wifi. Copying the video to the local SD drive would most likely have made it even quicker! The ESXI VM was competing with another five active VM's on my test server.
The Raspberry Pi still managed a respectable 195 minutes, which for the low power, cool running device it is and given the architecture is still pretty impressive.
Handbrake would have been doing the encode purely in CPU and not using the Pi's GPU either.
Given these timing I can see no reason why the Pi cannot make a nice little network attached encoding unit which can file watch for files to covert on the network and crunch away quietly.