There's still a significant difference between ~80% and 90%+ especially larger the home is. I'd always pick something at least around 92-95% of course I have a friend that does HVAC and he doesn't over charge me for the actual furnace. The price difference between them really isn't all that significant but it seems the standard is to charge MUCH more for the difference.

-Ben
HT v2.0
HT v1.0