when I rode my 950 through the mountains of Idaho and Montanna a few years ago, I had terrible performance and fuel range over 8'000ft or so.. which we hit several times on our trip. I went from around 170 miles per tank, down to about 120 miles per tank.. you'll get answers on both sides, but IMO, no reason to buy an older 950 unless you find a cherry one.
"ride hard, live righteously"
'04 1150 GS "Ich bin ein Berliner"
'12 KTM 690 - Austrian Ferrari