I have welded everything, down to weld on mufflers, random thin sheetmetal, the Tenzo racing seat rails I made for the hatchback, even crappy thin bicycle frames with an arc (stick) welder. I have ever heard you can do aluminum with the right rods but I've never done it. Most of this was overkill, but I can tell you 2 things I know.
1. It will look bigger/sloppier and you need to be good at it...it's less glue gun easy than a mig or tig.
2. Strength. If you are good and do it right it won't break, like EVER.
Downside is it will rust really fast, it's really easy to start fires and burn tiny holes and pits in random things.
I don't know when I will actually buy a mig or tig...I guess if I ever find anything that the arc can't do or I start to care more about how it looks.
You probably won't want to do this, just thought I would throw it out there since I have been a welding buff since I was 8 or 9 years old
One more note on the strength issue...this is how we have welded on the tongues to mobile homes that we have been tasked with moving from time to time, and we have twisted the tongue and warped the frame before the weld ever ever cracked or showed signs of stress.