Hi Manuel:
PPT's have certainly enterend the mainstream of contemporary education. Your point about customizing them is a good one, and demonstrates both the creativity and flexibility that technology affords active instructors.
What I've found with PPT's is sometimes there is too much information on a given slide, the slide goes by too fast, or information on the slide is incomplete.
One way to approach slides is to keep each slide to one point, with 2-3 complementary bullet points, or a enlarged segment of a diagram.
Regards, Barry Westling