I started figure skates sharpening´s with the machine which is basically bad copy of SSM-2. In that time it was cheapest new power grinder on the market and almost all local hockey teams used same machines. Person whom was "the official and approved" local figure skate sharpener used very similar machine. I was aware of Incredible Edger, and I dreamed about it, but I was too scared to make so huge investment when basically one-one believed that I can learn sharpening. I though that if existing skate tech uses similar machine, even this cheap machine cannot be so bad that I could not sharpen my own daughter skates with it. I used that machine some years. All that time I modified it and to be honest, I used too much money for updating that machine. Only thing I loved in that machine was almost friction-less axis movement (if you don´t use guiding roll in front of grinding wheel). All the rest caused lot of struggling, but I was still make better sharpening´s than existing skate tech. That is mainly because he used 5 minutes to one pair and I did use 1 hour. Shortly summarized, I do have experience also using 6" wheel machine.
Now when I have been using years 3" wheel machine, I would never-ever go back to large wheel machine. Not even the sharpening costs would be lower with large wheel machine. Are the material costs 0.1€ or 1€ per skate pair is irrelevant for me. Even-though IE has many things what could improved, I haven't found better machine from the market (personal opinion). I was considering also Blademaster BRPD1B, but I wanted to have almost friction-less axis movements, like I had on previous machine. Blademaster BRPD1B does have quite small table and I am worried about the friction when skate holder glides on the table. I do know few skate techs whom has purchad lately BRPD1B, so I will try one of those as soon I get change for that.