Answer- For me, the faster rods typically mean stiffer rods, translating to more work I must put into the cast. The GLX is touted as a fast rod, but there is a distinct difference in the feel of the rod. While the delivery can be considered 'fast action', the rod is a lot more flexible, taking on more work than the caster. It's nice to have a rod that does the working, so at the end of the day I don't feel like I've been pounding nails into a roof.
"A fly must first please the user before the fish."
Trey Combs: Steelhead Fly Fishing and Flies