Sorry I could not address that part, so much depends on the location, surroundings, signal strength, etc... Clearly an amplified antenna at the head is going to do a better job regardless of location as long as it has something to amplify. I am also not sure how much outside vs attic buys you, I never found much difference in Analog in a wood attic. I can see how it might make a big difference with aluminum siding or even brick.
Your post on the end of the locked thread was very useful, thanks. My only complaint is you did not specifically address the real crux of the issue. The fact is, many, many folks after the DTV switch will no longer receive acceptable signal levels w/o also employing an outdoor antenna. In this sense the 'smart antennas' will have limited effectiveness.