In my practical experience, a good quality 115 volt wire feed welder can work very well, and the limited duty cycle is less of a problem than you might think. Remember that that cycle is for full power, for one thing, and that you will not that often be needing to weld a straight bead for that long before you stop and look at it. If you get MIG, you can weld multiple layers without chipping slag in between. I would recommend that even if you need now to go with flux core (perhaps an advantage if you weld outdoors), absolutely don't get a wire feed that cannot be converted to MIG later.
I had a Hobart Handler 90 for years, and it did a great deal of good work. I recently gave it to my son, who is a sculpture student, and replaced it with a Millermatic 135, which is even nicer - fiddle free, easy to use, essentially just perfect of its type. The only time I've ever seen the Hobart pop its protective breaker was when I was teaching my son to weld, and he was making a rather elaborate sculpture out of rebar at high power.* For anything up to an eighth of an inch or so, I've never had any problem either with penetration or overloading.
By all means, get the biggest ballsiest highest-voltage welder you can possibly afford, but if you can't pull the current, don't be too afraid of a 115 MIG welder. If you later find you can run 220, you can always get a good heavy duty stick welder for the big stuff, and you'll still find yourself using the little wire feed for many jobs.
*note: my son wasn't a very good performer in high school, always on the brink of flunking out, and had hit a dead end on the "senior project," so since I knew he enjoyed art, I suggested he scrap everything, learn to weld, and do a sculpture. He came down for a few weekends, and did just that. The result was a rather interesting and elaborate sculpture made of rebar, that looked like a DNA strand, with various other things attached, culminating in a wicked looking drill bit on the top. as I recall, he called it "altar to the mosquito god." The school liked it, and in part as a result of that and some subsequent work in metal, he managed to get into art college, where he is now a junior, majoring in sculpture. If you should ever happen to be in the Beverly, Mass. vicinity, you might see brochures for the Montserrat College of Art, on the cover of which, under the heading "Art Changes Everything," is a wickedly redesigned office chair, his also. (Nah, I'm not one of those proud parents, not ME!).
