Couple other sheet metal tools I love:
Harbor Freight electric metal shears. Great for straight lines, and even radiuses. No clean-up. Really quite. No safety glasses required (though I never take mine off). It says it's good for 16 ga. If yo want to do that, buy the warranty. It will do it, but only for a while. Great on 18 ga, and smaller.
HF punch/flanger. Pretty slick. Punch works better than flanger. Great for lap welds. Oil often. They don't last forever. This is my second one...