Frame size alone won't tell you how well the bike will fit - a lot depends on the type of geometry the manufacturer uses. I just bought my new bike, tried a number of female or relaxed geometry frames, and am riding a larger frame number than I would on a standard / mens / aggressive geo. My husband is taller than me, and even though we both ride Felt but they are the same frame size number, my bike is too small (top tube) for him. (His is an F series, mine a Z)

I'd ask more questions about why a smaller frame is always better - better for what?

The build also will contribute a lot to the handling characteristics. Please don't take this as fact, but if I recall correctly - I read an article that stated a bike that feels squirly when you're standing next to it, pushing it back & forth will handle smoother at speed, and a bike that feels more stable while standing would be more squirly in use. I don't know which specific attributes make one bike feel more zippy than another - but I do know that I test rode a bike that Wanted to Sprint, and then the one that I bought simiply called out "ride me! ride loooong miles! let's go!"