iPad Can some back cases be used with other products

I currently have a Zum ultimate, frost, and black leather smartcover.
I am looking at the Zagg keyboard sales.

Are all the Zagg kbds, including the logitech model basically just as reliable as each other?

If I got the Zagg logitech, would the Zum Ultimate back cover still work with it?

Otherwise maybe I will go for a ZaggFolio...