I'd say that just because someone writes all their strips in a serial style doesn't automatically make their work a higher quality than people whose strips head off in whatever direction the author's brain takes them. Some of the greatest comic moments on this site were just one-shot strips with no backstory to them.
I won't deny that it's impressive to take a single theme and run with it for dozens of strips and maintain a high level of humor, but in the end, the quality of the author speaks more clearly than whether they write serials or not.
I liked your strips, by the way... until I got to the point where I realized that you were playing off of Donnie Darko, at which point I stopped reading them. It's a movie which I have not yet seen and don't want spoiled too horribly before I finally do see it.