My Full suss has the Hope Ceramic one, been in for about three years now, usually used atleast once a week, all year round in lovely Scottish weather, and lots of mud and grit from the trails, it's still perfectly smooth.
Hardtail has a Hope Stainless one, fitted three years ago to my hard tail, after 18 months in my full suss bike, normally used twice a week, whatever the weather, still running smooth, however both bikes once had Race Face BB, they lasted about 6 weeks of off road Scotland, which is a bit odd as I really like the Race Face chainsets, and they seem to be really good quality. I bought some spare bearing and tools to replace the Hope bearings, but I've not yet needed them.