Ned,
You might take a look at the HTP Invertig 221 specs. I debated the same issues as you and thought this was a good fit with some room to grow. Italian made machine and after-sale service and support had been above average IMO. The weak point is the manual which could have lost a little detail in the conversion from Italian to English but Miller's phone app makes up for that.
http://www.usaweld.com/SearchResults.asp?Cat=597
I also have HTP's MIG 200 and Microcut 600 plasma cutter, no problems with any of them after 2+ years.
Would I rather have Miller's equipment that's just a step above the HTP in specs.......yes, especially if I had a shop, but not for the dollar difference and my newbie hobbyist usage venture.