Expired is a great way to go if you have a lot of money for a good backorder service… if not, forget it. Don’t use the cheapies like godaddy… the scripts are inferior to other services.
Basically you need to go after hundreds of expireds just to land a couple. If you just target a few domain names, chances are increasingly rare of success because so many of us do backorder.
I have landed a PR-7 before and a few PR-6’s this way.
my2cents