First off I am a heavy industrial machinist so my welding experience has been large stuff, 50 tons or greater.
My partners and I have made 8 bumpers so far six front and two rears.
We have made one rock buggy so far out of a YJ, welding on custom king coil towers.
We have found that the 115 volt (mig) models don't have enough amps to make 100% penetration type of welds that we want to weld on clevis points, the towers to the frame and other projects.
For 50$ or so you can get a 240volt model instead of the 115 volt. Your home is prewired for 240 and getting that to the garage is not a big hassle.
My personal opinion is spend the extra bucks now and you will not regret it later on.