Flimsy sheet metal.
Build one out of wood so it has some weight and will stay inplace.

I agree - building one will be a lot more solid. I made one out of 4x4 legs, 2x4 frames, and some "plywood" that had a smooth finish to it (I'm sure it's technically not "plywood"). I think I spent well under $100, but it's been a couple years, so can't remember just how much.

It's a lot more solid than anything I could have bought!

If you want to make the legs and bracing solid, use two 2x4s for the legs. Cut a half lap joint in each leg piece and enclose the 2x4 stretcher between them.

I have almost the same Craftsman workbench from Sears.
I will tell you it's certainly not the best workbench, but it servers the purpose. I got it on clearance for 50% off, so it was less than $100. After having it now for a while, I don't think I would have paid full price for it, but for the price I paid, I feel like it's worth it.

I have one of these. I like it.

"flimsy sheetmetal" Maybe. But I have had it for about 5 years, 3 homes, and countless projects.

I have never had an issue with it not being solid. I climb on it, do some fairly heavy carpentry, and have the bottom bin packed full of heavy gardening stuff and bottles / cans.

I also have my nice wood ones, but this one is nice cuz the sheet metal is lightweight, and I can easily move it around.

-mike