We have a fritsch on a skidloader.  I think they're the same hyd motors it can with, we have replaced the seals a few times.  The seals go out when plastic gets caught on the edge and ignored.  It works it's way inside the drum then spins on the seal face and takes them out.  I don't think I've replaced one in the last 3 years or so.  I really have no idea how old it is.  It's over 11 years old, maybe 15+?

I face about 25 ton of haylage, 25 ton of corn silage, and 8 ton of hmc a day.  Corn is like nothing there, corn silage is similar.  Haylage works it a little, it's definitely slower going. There is a relief valve on it that protects it if you dig in too hard.  I've never timed it.  My guess is 30 min for all, but could be 20, could be 40.