Well, offhand I don't see why you couldn't use ereg_replace, but that's another matter.
Frankly, I use preg functions all the time, myself. Partly because I moved into PHP from Perl, but mainly because the regexp syntax used in the preg functions is much more flexible and convenient than the POSIX-style ereg ones. It also seems somewhat faster.
The only drawback I can think of is that it won't work on versions of PHP prior to 3.0.9, but who still uses those?
