I bought a used 195 over 10 years ago and have hauled lots of manure with it since.   Only real problem we've had was 2 years ago output shaft from the gear box stripped out where it goes into the lower beater.   NH has a repair for that, so it can be fixed.   Only other problem was cylinders on the slop gate started leaking.    Had dealer put in new kits and they work fine but if I had to do it again I'd just get new cylinders.   Not much difference in price.

I've got the single chain, never had trouble, just keep it adjusted.