Something people overlook constantly, is that auger point. Remember, those blades ride ABOVE it...if it isn't sharp and "pointy", you aren't going to have squat for cutting oomph. Check that point!
Like a good knife, if they knocked the angle "off" it CAN be brought back into the proper degreed angle, it's just a pain to do it, and you need to know how to do it. The smaller the angle like a 17-22 deg, will be a very fine cutting edge, but less durable. An angle of 20-22 degs is middle of the road. A 28 deg and above angle is very durable, but the "keen" edge gives way to durability. (most chopping tools, like meat cleavers, hand axes, are cut to a 30 deg angle)
IMO, some of these blades need a different angle compromise. Just did 3 high-end knives for a guy this Summer that had a place "sharpen" them, and had the 22* angle totally fudged. Took a fair amount of work to get them right. But then again, I've been doing it right since the late 70's....with 2 stones and honing oil.
