I prefer self-healing mats; mine is an Alvin brand mat I bought from Amazon and I LOVE it. It's a large mat so it's too big for me to soak it in a sink to rehydrate it, so periodically I mist it thoroughly with water and gently scrub at any lines with a green scrub pad and let it sit there damp for awhile. I cut batting on it and that tends to leave little tufts of batting in the cuts that prevents it from healing; this "spa" treatment removes those little tufts and helps keep it all nice and healed up.
I don't use the lines on the mat to cut with most of the time, so I try to make sure I'm moving my cut lines around on the mat and not always using the same spot. I think that helps them "live" longer too.