$count() is quite different for two reasons, one of which isn't so obvious:

Code:
if ($count($nick, username, someone, mirc1)) {


is an equivalent check to:

Code:
if (username isin $nick) || (someone isin $nick) || (mirc1 isin $nick) {


if the OP specifically wants to check for equality then this approach isn't suitable. there's also another slight difference in that, with $count(), mIRC will go through the entire string once for every extra parameter supplied even after one of the substrings has been found (whereas with an if statement the search is terminated once this happens). this difference might not become apparent for a small number of parms and smaller strings but can become a significant issue in other situations


"The only excuse for making a useless script is that one admires it intensely" - Oscar Wilde