The A719 rims have the greatest load capacity of their rims. They are welded at the joint as opposed the A319's being pinned. Welded joints may or may not be better, but in Mavic case I'd say probably. The intention is a smoother joint... which equals better braking surface. ..... if it's done well. Mavic's do it well in my experience.

Weather or not $25 per rim is worth it is up to each the individual. Considering rims are a long term investment, at least for most of us ..... I'd just get the A719's based on my previous experience with Mavic T519 welded rims, using canti's that is.

The A317 Disc rim is pinned, as a smooth braking surface doesn't matter.

All 3 tires take up to 47mm tires, though I'm sure it can do wider ones at lower pressure.