I use my Bowyer's edge quite a bit early to mid tillering, but put it away for chasing final tiller. The nice thing about a Bowyer's Edge over an ordinary scraper is that is has a flat sole that tends to prevent gouging at knots and grain swirls. It may still chatter, but won't dig in. The blade MUST be sharpened and burnished very well for it to work properly, but it's a dream when tuned up. Because of the frequent sharpening needed, I tend to use my Mystik scraper more than the Bowyer's Edge. It sharpens faster and alot easier with just a broadhead file, but I have to be careful that I don't repeatedly gouge wood at the tough spots. Tradeoffs. I'd love to get my hands on his rasp, too. I also use #49 and #50 Nicholsons alot, alternating with a Bowyer's Edge or scraper. The rasp takes off wood and removes scraper nicks and gouges, and the Bowyer's Edge or scraper removes the rasp marks. The tools compliment each other. Since that particular rasp is supposed to leave a smooth surface, I'd opt for that over the Bowyer's Edge, site unseen.
I sometimes use a farriers rasp as well, but only for the roughest work, before the bow is even floor tillered. It creates such deep furrows, that I consider it useful for only the roughest of work. Even the "smooth" side leaves an abhorent surface. More often than not, I go straight from a drawknife or bandsaw to a long handled Surfeform rasp, which is still a "rough" tool, but not so much as a farriers rasp.