Here's a recommendation that will save you a few belt grits, and some $$. Which ever belt you prefer, try using it in a 50 grit. Here's what I do..... rough grind with a 50 grit, then a 120 prior to heat treat. After heat treat I use a fresh 50 grit, taking the blade to nearly complete. THEN I jump straight to a Norax X30 (400 grit). At first it seems like slow going, but for me, it knocks off about 45 min- 1 hour on finish grinding, and eliminates at least 2 grits.......I save time, and money because I don't go through a 120 and 220 grit like I used to.
I've had the chance to test the 977s, and I would put them just slightly below the Blaze belts, what makes the difference to me is that the 977s are more costly than the Blaze belts....which to me puts them a couple of notches below the Blaze. I think it's worth mentioning that I really do think it depends on how you grind, and what you're grinding on. Most everything I do is forged, and is carbon or alloy steels....with those parameters I like the Blaze belts better. Hollow grinding on stainless might be a totally different game.