The Gitzo info was provided by their product manager at Bogen a while back.
To my knowledge the Benro/Induro are the same. Now how do they come up with the 8x label if not to go one up and mimic what Gitzo has already done?
You can go to the Gitzo website to get their tripod specs. They have revamped their tripods models to the newer G-Locks, so some models that you search on the web might have been withdrawn. Basically their models go by numerical series, the higher the number the bigger the tripod. Materials wise, it can be segmented into:
6x - full CF
Basalt - composite
aluminium
Any of the specialist ball head makers are reliable, it really depends on your camera load. Bottom line, Gitzos don't come cheap but they are demonstrably the best product on the market.