You won't find any usefull info on the crappy Boss website, only few features about each product and very brief.
It's realy funny that there are more info about Boss products on http://www.musiciansfriend.com than http://www.bossus.com !
You can always get more info from reviews you find in magazines or guitar sites like this.

But on the other hand , the company has an excelent reputation that you can rely on.

I have the GT-3 manual in text format, I can e-mail it to you if you asked.