I tend to avoid them, just of old habit... My first experience was when i put a space in a variabl name, and managed to destroy the mission...
I prefer to make long, drawn out events... I think for 2 reasons: One, because I enjoy thinking it through and making it work. And two, because i think its easier to debug. I'll compare the second statement to another situation: You are new to a campaign. You 'inherit' a half done mission from someone else. You have the plotline, but have to spend quite some time picking it apart, seeing how everthing was done, and either change your building style to use whats there, or redo everything to fit your standards. Most times its easier to just start over, and build it in a way that you know exactly whats going on. I choose to use long events, because that way i know exactly what is making things work, and often times, not work...
I'm pretty sure most people would use variables if they had to, but personal preference might make them avoid it...