I've used it's younger brother the 130 and it's older brother the 160.
Both very capabale machines on thin and thicker material.
The 140 I believe is the same as the 130 with a Euro torch connector.
We had a customer using one of the 130's on vertical up on 3MM mild and they said it ran perfectly.
I've got a gys easymig 140a, still learning with mine but I've been wedding van panels about 1mm steel on lower settings. The machine is good, easy to set up and use having the euro torch is also a plus
I have done car stuff with my 162 sometimes using 0.9 fluxcore, the 162 will do 0.8 sheet no probs, however, I would go 0.6 with gas if conditions allowed.
I would think the 140 will be fine.