953b, C, D.
Hi, Folks.
Well, I personally would hope that the 953D had a bit more going for it than the 953C. I ran a 953B with a 4-in-1 bucket - actually an old 950A bucket adapted - a/c ROPS cab and rippers for over two years. The same company also had a 953C with a standard 4-in-1 bucket (the bucket on the 'B' was about 10-15% larger), a/c ROPS cab and rippers.
The 'B' was far and away the better machine. It handled the bigger bucket with ease, had more grunt, dug, ripped and pushed better, handled hilly ground and slopes better and was generally a much more user-friendly machine. And it DIDN'T have electronics - which meant that we could fix a lot of what little trouble it gave ourselves. Ask KoO about this aspect.
In reasonable digging with the 'B', I could send a 10 metre tipper away loaded in 3 1/2 buckets every time. It was always 4 buckets plus with the 'C'. In fact, on one job, I was working alongside a Cat 350B excavator which was loading the same trucks in just half a bucket less than I was - - - and the 350 was 3 times heavier than the 953B. And it burned a bit more fuel too, not to mention being harder to move.
Just my 0.02 cents.