As we make papercraft creations i try to avoid other materials as possible,so i use paper except when i need to make windows where i use transparent plastic.you can see an example in the photos.they are strenght enough for paper constructions.i used the thinner one in formula one car(see that in gallery).the car is moving like a hot wheels metalic!
i think that paper pipes are better because you can choose precisly the sizes,and if you want more strenght you can paint them,remember that the glue also make the pipe more strenghth.