Hello seppo, and welcome tho the friendly Camera Labs forum!
Let me just get back on your last remark: Did you have a chance to look at my "Big ultra-long zoom test" here
Apart from the Sigma 80-400mm OS there should be most qualified contenders in the 80-500 range present. Unfortunately the Nikon was the clear winner here, so it seems to hold true again: you get what you pay for.
I'm personally betting on an upgrade of the old Nikon design to make a truly stunning 80-400mm...
Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews
, My Pictures
, My Photography Blog