I am using Samson Ultralite 3/8" through a 7:1 old-style low profile Harken setup. At first I found it to be slick and hard to grab, but after a month of use it fuzzed up a little and has become very nice. I am running 2.25 blocks though, so it is not as smooth as I would like.

I also have a question for anyone out there with carbo mainsheet systems: How much better are they and is it worth $300 to upgrade?

I am seriously looking into the 8:1 system. My experiance with Harken's carbos so far has be excellent on other parts of my boat.