When I was a child growing up at home, my mother ONLY bought Imperial Margarine sticks. I never knew it wasn't butter until I got older and started shopping on my own. It was the only thing I ever used, along with Crisco, for baked goods.
The only thing you can do is give it a try and see if it works for the recipe you have. I agree that I would only substitute with the hard stick type and not the "soft" tub type margarine. Actually, if you go back and look at some old recipes on the internet, many of them call for margarine or "oleo", which is another butter substitute.