I wish this topic would become a sticky it seems to come up every week or two. With all the "hype" out there, people seem to be confused for good reason. The bottom line is you will not see any difference at all. From a 5.565, 5.7, 6.0 rod the differences are so minute you will never see or feel any difference. The whole side loading, more time at TDC etc is not worth wasting time on. The differences between them are so minor/tiny, do a search on rod length and see what comes up on this site. A lot of people have "opinions" about this, but very few have "facts". Find the facts and decide for yourself.
Buy the best rod you can afford or can get the best deal on, that will work for your application.
I guess that's just my opinion as well, huh? LOL
EDIT: The study above is one of the very informative (fact) things I was talking about.