I agree about using MIG over other welders. Not only are they forgiving when welding, but there is less that can break. MIG welders, and even spool guns, have too many moving parts to feed the wire that can break and leave you high and dry. A MIG setup is as simple as it gets. Two cables, two clamps, a welding stick and a power source.If you are wanting to weld around/through rusted/painted metal get a stick welder. Migs are great but clean metal is a must for the m to work right. A stick is much more forgiving about this.
I have never used any of the welders you are referring to., I built my own out of a alternator. I can adjust the power by varying the engine rpm. I have used it quite a few times on the trail and in camp. Works great and the only part that might go bad is the alternator and I can get a replacement at any junk yard for $10 (or buy new) do a quick mod and I am back in business.
The plus side of this in my opinion is the fact that if my normal alternator goes bad I can un-mod my welding alt move it in place of the bad alt and be on the road again.
Food for thought anyway.
Do you have any pics or diagrams of your setup? Especially wiring diagrams. What alternator did you use and what are you powering it with?