All of the vehicles in my sig have the original converters, but the BMW is OBDI so I really don't know if those are working or not. I've seen inside them and they are still intact and haven't overheated or anything, so I'm guessing they are.
227k on my Camry's cat.
I had the one on my Jeep replaced last year, it was broken inside and rattling around. It was dented on the bottom so I bottomed it out off-road at some point that probably broke it.