I don't know that much about Cockers, but I went for a pup from show lines as I presumed a working one would be more active.
I was talking to an old couple at the vets a couple of weeks back, they had a young working Cocker. They said they went for a working one as they thought it would be much quieter and calmer than one from show lines! I told them I thought it would be the other way round, but I don't think they believed me
, I just hope their boy stays as quiet as he was, as I am not sure they would cope with him otherwise. From what they said he was their first dog!
Oh and the vet said how calm and well behaved my daughters Cocker was