The major downside of the Tormek is the speed, it takes forever to get a new bevel on a wide thick plane iron. And when I say forever I mean it. The bevel up blade for my Veritas shooting plane took about 1 hour of constant grinding with some small pauses. I was extremely frustrated at times and went for the Pro Edge instead.For flatwork tools though a wet grinder may be a better choice? The only downside is the water.
Pro Edge has it's downs as well, it's difficult to get an absolute straight edge on things, but I only use it for primary bevels and for that it works great and is fast.