I went from a Trek FX hybrid to my Long Haul Trucker, and the LHT definitely feels (and is) faster. The LHT also probably is in the 30 pound range with empty panniers, daily load is probably more like 35. It's heavy, but efficent, and oh so smooth.
My Hardrock is light like whoa when I put the "summer" slicks on it, I notice that it's faster to get moving and to lift, but beyond that it's negligible.