First off it is a very good article and pointed out something I never noticed before.

But I do agree with Chris.

Only when the name of the executing SP was different in case did I see a CacheMiss. When the name of the parameters were not exactly cased the same it made no difference.

And I never saw a recompile occurr or a new CacheInsert. I just saw a CacheMiss. Of course this still means a performance degrade on high transaction systems.

As for the question earlier about how many would you say before you consider it bad. I would suggest any, you just simple want to avoid as much unneeded work on SQLs part as much as possible.