Agreed about the eight down. I had the 6120 and bought the 6141 and have been using it for a few months. My area does have the 8 channels down with 2 up and I did notice things being more constant with the 6141 than they were with the 6120. I don't know how congestion is determined, but a Comcast tech told me there were only 31 subs on the node I am on. The 6120 had no problems, but I like to have the latest for things coming down the road.
I live in a pretty rural area with few houses and a resident moose or two walking around. I guess you would call it the boonies. The plant was put in all new in 2001. The only thing I could figure was it was AT&T at the time and the regional manager for AT&T lived 3 houses away.