I always prefer less leg sections, 1: less time adjusting the legs to get into position, 2: in theory, its going to be more stable, for the simple fact that theres one less "joint". Also, the more sections you have, the thinner the legs are going to be at the bottom, which may or may not have an effect on stability. Ive always tried to keep the bottom section extended the least amount as possible to avoid any potential stability issues anyways. While you may only use it for positions up to kneeling, expect the possibility of using the tripod in the standing.
Is having 3"-4" less when folded, going to make a big difference in compactness for you? Do you have the extra 1-2 seconds per leg section to adjust all 4 sections in order to get the tripod to proper height? Granted the time is probably an extreme factor, but it may help in your decision. For kneeling, you may only have to adjust 1 section per leg to get proper height with a 3 section tripod, but with a 4 sections theres a possibility of adjusting 2 sections per leg. Just things to think about.