As for climbing, the 1001 and 1002 use the same linkage with basically the same kinematics to the 135mm point — the 1002 just puts a longer shock on it. They both climb quite well for a 4-bar linkage.
Nobody has compared the 1001/2 with the 1003 head to head — I hope to be the first, in a few months — but all descriptions are of it climbing very well for a long travel bike. Looking at it, I bet it climbs just as well if not even a little better than the 4-bars. It’s a slick little design, very well balanced in all its attributes.