FWIW, I haven't upgraded to Lion on my music machine. Still running Snow Leopard because it just works well with my music programs (PM and Amarra). WRT iCloud, I'm not so sure you need Lion. I started my iTunes Match account on this same machine, and it works like a charm. It matched what it could and pushed everything else to the cloud. I know iOS5 is required for iCloud.
EDIT: You're right. You do need Lion for iCloud. I thought that since iTunes Match works on Snow Leopard, it wasn't a requirement for iCloud.