One thing considerably faster? (And when so, is the fact that simply because it's designed in C, or because of another optimizations?) Capability to eventually do load balancing? Getting plenty of
mod_anything you could possibly want here?
EDIT: I suppose my question for you is, just what does Apache do in a different way that causes it to be so common/well used?
Apache is free of charge and snapped up marketshare age range ago. Now there's sufficient expertise and proven reliability (ie, status) it's a recognised player within the webserver market and it is not going anywhere for any very long time.
I would state that your real question is wrong. It is not "So why do people choose Apache?" It's "Why wouldn't people choose Apache?" This is the energy of the established market presence along with a lengthy-term dominance of the particular segment. :)
Quite simply, It has hardly any related to the technical facets of the items involved.