I don't know what you are intending to use the welder for, but why not go to 220V if you are installing a dedicated circuit as it will open up you options tremendously. Probably will cost the same.
110 volt machines are limited in output and duty cycle due to the fact that 110 volt circuits are limited to the 20 amps max.
A 220 machine can be higher output and longer duty cycle as there is twice the power avaliable from a 220 volt 20 amp circuit than a 110 volt 20 amp circuit. Power (Watts)= Volts x Amps
(220V x 20A=4400 Watts, 110V x 20A = 2200 Watts)
I made the mistake of buying a 110 volt machine and found that I was light duty and only good for light sheet metal work. Sold it and replaced it with a 220 machine that I can weld real stuff with. My $.02
Ted
