Bang for buck, Unitig AC/DC 200 amp. You will need to buy a foot pedal for it though, and 15A GPO.
I have used one daily for about 5 years, good unit. Only once did it let me down, a circuit board blew out, but the replacement part was on the shelf in Sydney. I just can't justify buying a Miller for 5k when this one does a similar job for 1/4 the price.