Whitequark - I am sure others have but our needs are pretty basic.Our only involvement with sheet metal is to design convector-boxes for woodburning-stoves in a variety of shapes and sizes. SolveSpace looks to be the perfect tool for this since we can alter the parameters in seconds to suit almost any requirement.
I attach a sample of my first, faltering efforts and the things that come to mind are that (a) I would like to be able to turn REF dimensions on and off. They are a quick and invaluable way to check that all links are behaving themselves but clutter up the drawing needlessly when all you want to access are the few dimensions that drive the rest.(b) An ellipse tool would be great. (c) My efforts at constraining arcs & circles in 2D result in a spider's web of links going in all directions that are then rather unstable. In an earlier posting Jonathan recommended sketching the un-drilled sheet, extruding it, then adding the drills as a Boolean difference which I'm sure is an option but rather a long-winded one. Not nearly as simple as the excellent tool provided for radiussing corners!