From a physics standpoint, asymmetrics have a significant preferred spin axis (in addition to the one at the pin that all balls have).  Symmetrics don't.  On a machine like a deTerminator, an asymmetric ball will find its PSA in 5-15 seconds, while a symmetric ball will take much longer if it finds it at all.  The lower the spin time, the stronger the asymmetry.  The strongest asyms today are in the 5-5.5s range, while milder ones are closer to 10-12 seconds.

There are several ways to create asymmetry: adding mass to one side with core shapes (Track's bread and butter), density changes (The One series and the X-factors and Paradigms do that), or by stretching a symmetric core (the current Zone core).

SH

Medium to strong asyms tend to be more angular than comparable symmetric counterparts.  It's hard to say because there aren't that many cases of a symmetric ball that's similar numbers-wise and cover-wise to an asym.  The most obvious example is the Inferno/Zone balls.  The OI and ZC were similar balls for similar conditions, but the ZC was more angular and slightly stronger.

But medium to strong asyms are so versatile and the MB placement has such a strong effect on ball reaction that you can get a wide variety of reactions out of them.  You could make that ZC much more angular, but you could also make it smoother just by adjusting the MB location.

SH

The Total Inferno is symetrical.
--------------------
(\/)
(..)
c(')(') Chuck Norris doesnt believe Germany.