I agree with @psulion22 I work part-time in a shop and sharpen my own skates we use the spinner system to dress the wheel. I have been skating at 5/8ths for probably about 10 years. A friend of mine has a sparx and I was curious so I had him cut my skates at 5/8ths. I was there when he did it we did 8 passes on each skate. When I tried them out they didn't feel like they had the same bite as when I do them on the blademaster. The best way to describe what I felt was a 5/8th sharpening that had been skated on once or twice. For me when I no longer have access to a sharpener i'll probably buy the blackstone portable machine. This was mainly a test to see if I would buy a sparx over the blackstone.