I have a Miller 185 (use 75/25) and for thin metal I use my trusty .030 wire. I am no more than a dangerous Stunt Double when it comes to welding. The more I do it the more I really respect people who have the knack.... I just replaced a partial Floor Pan and struggled with it at times but with patience and good grinding I am satisfied with the results.
I really lost sleep over which machine to buy but I needed something to cover all types of welding. I keep saying to myself that a Tig would be nice for Aluminum and thin Metal but then I go on youtube and see people do bodywork all day with a Mig.
Whatever you buy make sure what you get is dual purpose and uses gas.... As for brands, zero issues with my Miller for 10 years...
JW