Lots of difference here between the two models. I sold a 950, and have a 970, both 4wd. 970 has a 4 cyl. diesel and runs much smoother than the 950, easier to start the 970 by far. 970 ( at least mine ) has a synchromesh transmission, don't have to stop to change gears like the 950. Seating on the 970 seams much more comfortable than the 950, easier to get into and out of. I also had a Yanmar YM 3000, very close to the 950, both off the same production line, YM 3000 very close to the 2 wd. 950., some parts interchange. The hydraulic pump on the 950 is on the front and bottom of the engine much like the gray market Yanmar YM 3000 and use the same pump as the Yanmar. 970 uses a different pump on the left side of the engine, looks like it might be 2 pumps in one body. Both of these tractors are made in Japan by Yanmar. 950 ( at least mine ) didn't have power steering, my 970 does, makes a huge difference when running all day. Also, in the 970 series, sound dampening panels were in place on both sides of the engine and this made for a much quieter tractor to run as the operator. As a guy who rebuilt a 950, I know some of the parts were becoming hard to come by 3-4 years ago, and this will get worse as time goes by. The 970, at least for now, seams fairly well supported for parts. If I was looking at both a 950 and a 970 with equal hours, and in equal condition, I'd value the 970 at least worth $2500-3000 more than what the 950 is worth. ( bare tractor ) My 970 came with a 80 quick detach loader and a #8 backhoe making it a 970TLB. ( Tractor-loader-backhoe ) I sold my freshly rebuilt 950 ( bare tractor ) for $6500 and bought the 970 ( with the loader and backhoe, lift arms, and drawbar ) for $12,000. After using the 970 for the last 3 years, I'm very happy with the deal. I'd recommend the 970 over the 950, even if they want $3000 more for it, good investment. The more hours you are going to spend using one of these tractors, the more worthwhile the extra investment becomes. Lots of 950's and 970's out there, quite a few of both made. Hold out for the 970.
Chris