I still love my C220 nearly ten trouble free years later. I sold the 275 IV to make way for 501s but still miss its way of making everything sound good. The 501s are more accurate and that can be good and bad.
Never had an issue with any of them, or the 40 year old MR77 either.
Never had an issue with any of them, or the 40 year old MR77 either.