There a bunch of threads on this topic on the old forum. Here are a few articles about it.
http://www.no-gi-grappling.com/no-gi.html
http://www.no-gi-grappling.com/no-gi-vs-gi.html
http://www.no-gi-grappling.com/no-gi-vs-gi-2.html
http://www.no-gi-grappling.com/no-gi.html
http://www.no-gi-grappling.com/no-gi-vs-gi.html
http://www.no-gi-grappling.com/no-gi-vs-gi-2.html