Thanks for your comment.
Maverick and W8.1 aren't (yet) there and I will certainly wait for the dust to settle... I don't need support for up to 16 vCPUs, 8TB disks and 64GB of RAM (hopefully this will be the case once I get the new MacPro 
). There are then the "over 50 new features" which quite honestly are the reason for my initial post - there might be something here that I missed.
Good point about the 30 days demo - but It's not always possible to downgrade (I'm pretty sure that some / many features are only available it I upgrade my VMs... ). Anyway comments / reviews most welcome !