I just replaced my old Miller MM 180 with a new Miller MM 211, after a conversation with TIG 1, looking at them at the dealer actually trying them out and doing a lot of research I went with the new Miller inverter machine.
The old machines like the Lincoln and my old 180 are transformer based, not that that is a bad thing they are just heavy, have a shorter duty cycle and use more power for the same output but have a long and proven track record for high reliability.
The new Miller 140 is also inverter based, is lighter and more portable and the Lincoln 140 competition.
The 120v is fine for light stuff and is well suited to automotive work especially sheet metal but the flux core wire sucks, lousy looking welds and needs more amps that can blow holes in sheet metal, gas is the only way to go for this sort of work.
I use quick connects on the regulators and separate guns so I can switch gases and wire size quickly without having to swap the gun liner for smaller diameter wire, it also makes the unit more portable with a small bottle.
Consider a small bottle with a quick connect (cyberweld.com has them cheap)and use .023-.025 wire in these small units, it requires less amps and is less likely to blow holes in sheet metal.
The Lincoln is a good little welder, I looked at the 180 dual and Miller 211 and was torn between the two.
What I liked about the Lincoln..
Small size so it fits on inexpensive welding carts with no problems.
The angled all metal drive system.
Transformer based.
Nice ground clamp
It has a good name.
Good cash rebate or free Lincoln auto dark helmet and jacket/gloves package.
3 yr warranty
What I didn't like..
Made in Mexico.
Transformer based. Yes I like them and dislike them at the same time.
Heavy.
Cheap feeling controls. I don't think they are cheap, they just feel like a 1970's AM car radio.
The miller 140 is its direct competitor and is similar in size to the 211 I bought but its not dual voltage and less power.
The likes..
Made in USA.
Angled all metal drive.
Light weight just 38lb.
Smooth as glass controls.
Auto set with different gas settings.
Inverter based unit.
Auto cooling fan control.
3 yr warranty
Dislikes..
Size, it is longer than the transformer based units requiring a larger cart.
Power switch on the back of the unit.
Inverter, while proven technology it is fairly recent in this size of Miller machines (more electronics?
Price, it is more expensive, only time will tell if its worth it.
Cheap Cheesy ground clamp, it looks like they robbed it off a set of $5 jumper cables from Walmart. That went in the trash right out of the box and replaced with an all brass Tweko.
I think its a coin toss between them, I was honestly frustrated going back and forth between the two. Both are good machines. I have 220v but run it on 120 for most of the work I do which is mostly thin sheet metal and thin metals less then 3/16", it does fine.
For thicker stuff pop it on 220 and it becomes a different welder, the inverter is a much smoother arc than the transformer machine.
I think what pushed me to the Miller was the newest generation of Auto Set, It seems very accurate on 120 or 220v even on 18ga sheet metal and the additional 30 available amps.