Before I pulled the trigger on my first straight, back in my Mach 3 days, I switched to a brush and soap and I'd say it improved a cartridge shave by at least 20%. And the upswing is that when I received my SR my lathering skills were somewhat proficient, which eliminated one variable right away.

As for using a brush and the canned goo, I've heard it works in a pinch but traditional soaps and creams are better for your skin in the long run.