Don't Do IT!!!!
Slower than snow leopard, No Supports for NAS drives. Front Row Deleted. Any power PC Based Application will no longer run as they have dropped support for it. Inc Most Adobe Software, Logic 8 - no support, Toast - no support. Microsoft Office 2011 only no 2004/2008 The list goes on.
If you are not sure - read the posts on the Mac App store review section.
I work as an apple reseller and we are getting 100's to complaints of hardware and software not supported.
I would go as far as to say Remember Vista!!!! Well apple just made one of those.