There are different kinds of composites and different ways to classify
composites, but none are "better" than the others per se. It really
depends on which job you want to do with them. Thus, you've got
composites with great colour stability and excellent polishability for
use on anterior teeth for a very good aesthetic result. On the other
hand, when you take the posterior teeth, you want a durable composite
with high compressive strength and wear resistance.
Unfortunately, there is still no composite that will meet all these
requirements, so you have to balance all these factors and make a
choice based on what you consider important for the task at hand.
If your friend just said "white fillings" instead of "white composite
fillings" let's not forget a whole class of underrated (IMHO)
restorative materials: glass ionomer and its derivatives. The original
self-etching, self-bonding, slightly moisture-resistant dental
restorative. Great for deciduous teeth and quick patches, but virtually
unused for "serious" restorative work by most dentists I know
(including myself; I've only done one MO filling using GIC on an upper
first molar - still there after 2 years).

George

There are different types and dentists have their favorites.  I'll list s
few and tell you which I use.  In general terms the composites are composed
of BisGMA resin and pre-cured composite particles.

Macro-fill = larger particles, less shrinkage on light-cure, used for
posteriors where extra wear may occur, "stronger", less polishable.
Micro-fill = small particles, more shrinkage on light-cure, used for
anteriors where esthetics are important, more polishable.
Hybrids = "mixture" of the macro and mico-fill, medium shrinkage on
light-cure, used on posteriors and anteriors, average polishability.
Nano-hybrids = "marbles in a glass".  Particles are spherical rather than
chunks, medium shrinkage, used on posteriors and anteriors, better
polishability than conventional hybribs.
Flowable = makeup of resin:particles allows for flowability of material,
highly polishable, will wear faster than other composites.

Glass-ionomers (GIC) = fluoride release, "wetable" supposedly.

I use Nano-hybrid composite (Grandio by Voco) and Flowable composite at my
office.  I sometimes use GIC (Dyract) for certain root caries.