I tried that method (the quilt show one) on the quilt I'm making presently, which has lots of borders. I didn't find it worked all that well. I still ended up with one strip in 4 having a divot at the fold. I've tried the shape cutter by June Taylor; it works well as long as you have a new blade. I always end up messing up at least one blade and/or having to go back and try to line stuff up again because I didn't cut all the way through. I have a Go Baby with the 2 1/2 inch die that works pretty well, but has to used on the length of the grain.
I just went back to cutting carefully with a ruler - on this quilt anyway.
bkay