Hmm, if I can write something in a couple of minutes that your friend takes a couple of hours to write, I can take a 118 minute coffee break while my program is running and your friend is still working on his program. And so for the first run we'll probably be done at about the same time. For a throwaway program, or for programs where the time difference isn't so great (such as when doing database access) I prefer doing it my way. For a time-critical process that we're going to run alot, and is not likely to change much (and if his is really 100 times faster), we'll use mine as a prototype until your friend finishes his.

The difference in runtime can be up to 100 times faster for C, but depending on the task, isn't always that great. The difference in development time (and in making modifications) can be the same but in perl's favor.