I've been debating this myself. I have a sectional that I bought 5-6 years ago, microfiber material. Kananga has already dug through the material where he sleeps (at the corner of the sectional). I had flipped the cushion once to hide the damage, but he did the same thing to the other side.
Leather just seems much easier to maintain. No worries of accidents, and I'd imagine the leather will just be more durable (depending on the type).