Because of the PHYSICAL size differences between Atwood and Suburban you are better off STAYING with the brand that you have.
The Atwoods are a bit taller and wider than the Suburbans and the Suburbans are a bit deeper in to the camper than the Atwood.
My TT originally had a Suburban but the previous owner replaced it with a Atwood, to get the Atwood in the PO removed and DISCARDED the Foam INSULATION :S That was the ONLY way it would fit.
I altered the opening in order to PROPERLY fit the Atwood.
I had a HARD time FINDING just the insulation, just not something that everyone carries. Cost me $50 for the insulation PLUS oversize shipping charge of $25 on top of that :M