I only use DVDs. Our internet is unreliable, but even if we could depend on it, I'd still use DVDs. I like having a visual on my bookshelf. It represents how hard I've worked. I feel a sense of satisfaction when I slip that DVD back in its case on slide the case back into it's spot on the bookshelf. It's the final step in cleaning up my workout space, and it makes me feel like my workout is complete. I find myself kind of thinking, "a job well done" as I put that case away. Then, I reward myself with a piece of dark chocolate! lol