It is true that there are more people at PacBell and MAE-West than
there are at PAIX (for now).
How that factors into the relative worth of connecting at an exchange
point is up to the individual. While Nathan may feel that there are
not enough people there to be worthwhile, there are others who feel
that there are, or who assign that factor a lower weight when deciding
where to go.
Every exchange point has its pros and cons. How they are weighted is
up to the individual.
There are good reasons to go to PAIX, and good reasons to go to
PacBell. They depend on what you want out of an exchange point. The
more information you provide about what you want from an exchange
point, the more likely that the discussion will objectively evaluate
the exchange points against your criteria. The less you provide, the
more likely we'll all just rehash the obvious.