IMO, buy the most powerful machine you can afford, I can't see as a hobbyist that duty cycle matters much, and forget anything flux core I have a hobart 140amp 120V mig (for 20+ years, and exceed the duty cycle all the time) With the cars, I find myself using the Hobart the most often.
Has it's uses outdoors where maintaining shielding gas could be an issue.
Yes flux core has many uses. Some even use flux core with gas, if makes for good penetration and nice looking beads. I have used flux core in my spool gun outside on dirty/rusty steel.
