Hi one question ,how big will be your works?if is for motorcicle parts or something similar the Nitro will do a good work but if is only for the hardness of the metals the classic can engrave all the engravable type of metals if you need more power only you have to buy the tungsten piston, nothing more.
For me The Palm Control is the best tool of the market, and worth every penny that cost, i had buy the foot controlled first and after i have make the update, ever is an option, if you came from hand push graver you will love the Palm control, for me is much more intuitive and the control is much more better than the foot control.
And remember that the nitro need more power and psi to work, at the end if is only for the hardness of the metal the classic handpiece can do all the works without problems
