From a theoretical perspective, nothing will be faster than Catalyst and still block just the messages necessary. If you block more than Catalyst-- then you're blocking events that are likely necessary for mods to operate correctly.
It wasn't a study.. it was one person posting a non-scientific study. Regardless of that, WT (if at all) would provide an extra 4% improvement (to pick an arbitrary number)-- and given the way its coded, etc. I wouldn't touch it.
WT goes through and has a list of addons, and the events you should block from each and is basically a band-aid fix for each frame in the game.
Catalyst recursively goes through every frame in the game, and hooks all the event handlers (Where they exist) using safe hooks. During the zoning period, it only lets through events that aren't in the blacklist (bad events that aren't necessary). It then unhooks and goes away nicely.
One is a general solution to the problem, another is a not as well coded personalized solution for specific mods, and tries to handle the general case as well.