My main beef with SheepShaver is that it has relatively poor compatibility. A lot of things cause it to simply freeze up. In fact, you could run Copland on it and not tell the difference.

Basilisk II isn't bad, but isn't PowerPC.

I have SheepShaver on my BeBox but it's abysmally slow. Classilla will run but at a glacial pace. I'm still periodically hacking the source to make it build on my AIX POWER6 ("world's fastest Power Mac").