I have used and sold several sets of EPI Belly Buster weights. I always liked how hard they hit and compared to stock. BUT recently bought a set of BB 66 weights and they had the exact same arc as the stock 68's my 2019 850 AXYS came with except they were thinner so more wear on the rollers are expected.
They are working well for what I am using them for but I am a little disappointed that they did not seem to be as heel weighted like the 64's I used in my 800's. I now have a set of SSI adjustable weights on order but they are back ordered at this time. They are cheaper too. My favorite weights are Dalton adjustables as they have the set screws that screw through the core and can be adjusted easier than a side weighted adjustable ramps. Daltons are expensive though.
So short answer is no Belly Busters are not worth the high price.
I use them all the time. I don't remember what weight but after a certain weight like 62 grams or something the profile is the same. I do like the finish quality better and they weight is more consistant from one to the next. Never had to grind to balance. I'm running 10-70 belly busters at sea level in my 800HO.