I don't know - it might be worth a second look to see how performance REALLY is impacted. That's a fairly vague statement in the OSS note, so it might be worthwhile to create a view with that above definition and run side by side vs. the standard. Just querying it for a single user should give you enough information to make an informed decision.
It might come back that its 40% slower, but we talking 100ms vs. 140ms, know what I mean?
If you are considering a workaround with a SP handling security running every 5 minutes, then it's probably worth considering this as a more "standard" approach with a few lines of code one time only 
Regards,
Justin