I have a Weber Go Anywhere BBQ that is very robust - will not warp or rust when used as a BBQ because it is enamelled steel, not painted. I know people who have had the same Go Anywhere for 15 years and it is completely unwarped and unrusted. Also the lid and vents allow roasting as well as grilling.
Not sure how it would function as a fire pit with a wood fire in it, for example.
We used to use a good Whitstable bucket BBQ and then put some logs in - but it did rust through eventually. You need a proper galvanised bucket model, not the 'pretend' teeny panted ones from Sainsbury's etc.