Really it depends...on race boats yes...there is faster boom moves, the winches normally are two speed allowing fine trim, and allow better control by a main man. Its just a more practical solution with less effort, and mainly a speed reason. Also and a big also...it allows the main control from either side of the boat, as the main sheet is a continuous loop. So In fact, while sitting at my wheel on the high side I have both sails controls near me..as I tack, I move to the other side...and BINGO...same sail controls there!!!! clever, huh??
The purchase system is normally used on smaller boats, altough some large racing boats also have it with a larger purchase for course trim, and a smaller purchase in series for fine trim. I don't like it...takes a lot of speed from it.
In a boat like the GS...it really is not that important...you are not racing..just sailing fast...
its pretty good too...you will not sit right behind the whell, like on a Formosa...you'll be sitting on the side...enjoying balcony view, sheet at your feet!!!
I would love to make you a drwaing, but have work to do, and my IP does not allow photobucket access..I'll try tonight at the Hotel