Rotatrim Size Recommendations

I'm thinking of getting a Rotatrim but am uncertain on what size to get.  I would primarily use it to cut paper so the 24 inch would seem to be fine.  However, if it can be used to cut single thickness mats I would get the 36 inch.  The specifications seem to indicate that it can cut single thickness mats, but some posts seem to indicate that it cannot cut mats.  Can it cut mats?