t/s specs and theoretical comparisons

Ok, time to throw sealed enclosure vs vented enclosures into the mix. I have done some simulations before using WinISD... It's been a while, but my overall conclusion was that sealed boxes have better low-end response and sq but ported boxes could be tuned to peak hard at specific frequencies at a significant loss of sq or tuned for smooth responses at a loss to some of the lower frequencies. IIRC, I seem to remember that when I simulated a ported box designed to have a smooth freq response, and a sealed box of about the same volume as the ported one, then the sealed box often had higher simulated output... Thoughts?