I have used the TD inverter Mike is talking about is is pretty mean for a little machine but it is not cheap. The guy told me he gave around 2300.00 for his and I about fell over a little more and you could buy a base 250 Syncrowave and have a welder most of us would never catch the duty cycle on. I have a 180 Syncro. and an old Lincolin 300/300 and it will do anything you ask it to but sit down when you get the power bill. If I was going to buy new again I would look at the 185 Lincolin (it may be a 190 now but a few years ago it was a 185 squair wave) it has some of the features the 250 Miller does at just a little more than the 180 Miller.
Have fun with the new toy what ever you buy.