I use Kiwi slides. They come from http://www.anzam.com/rr_index_003.htm
. They are easy to install, very low tech, very durable (at least in my low test sailing area - the Potomac River) and very inexpensive compared to all those systems. I am able to hoist my 250 sq ft main without a winch without any trouble. The only shortcoming thus far has been my amateurish sewing, which I have had to repair once in the last year.