the strap cutter definatly works better on certain types of leather, thin, stretchy, upholstry leathers don't seen to work as well.
http://forums.timezone.com/index.php?t=tree&goto=2532389&rid=2003
i use a similar method to the 1 in this tutorial, i cut my strips wider than i need and then trim them to size once glued, with softer leather having it doubled/lined it keeps it from stretching, and makes my edges better. using a utility knife take some practice aswell, just make sure its sharp.alos make sure your ruler has a cork backing.