you have been told correctly, welding with a MIG machine is very easy. in comparison, stick welding its like using stone age tools
if money is not an option, i VERY VERY highly recomend a 'Miller" brand welder. they are simply the best, and their customer service in unbelieveably good.
Specifically, the Miller PASSPORT. this is the most amazing welder ever. if James Bond was issued a welder, this would be it. in runs on ANY voltage (90 to 380) at any frequency and any waveform (that means you can run it from a crappy generator (with poor voltage.freq regulation) and still get top preformance without overheating, derating, or destruction. it is housed in a suitcase... so just carry it where u want it (only 45lbs) and weld whatever and wherever u want (oh, the shielding gas tank is also included INSIDE the suitcase). it will weld just about anything (reasonably).
oh, at least for me, the investment in an 'auto darkening mask' was the single most inportant factor in improving overall weld quality,and general welding bliss.
a 110 volt machine would work fine for a go cart frame, but ... you never know what you may want to do in the future. buy a good one and be done, period
well, just a few thoughts, hope this helps