I would like to help anyone considering these two products.  Full disclaimer - I am the CEO of Sparx and a MSH member.  Sparx and ProSharp Home are BOTH good products.  That said, there is some misinformation in this thread that I hope I can clear up. You cannot directly compare Sparx to ProSharp on the amount of sharpenings per wheel that each company advertises the life of their wheels at. Reasons: 1.  The two machines remove different amounts of material per pass.  Sparx remove