I had 28 Mudzillas on for a while, they worked quite well, but I always had that feeling something was ready to pop. I now have 26 swamplite on my rig and feel much better. For the extra inch of clearance it might be costly. I suggest you borrow a set of 28inch tires from a friend and try them before you buy another set of tires.
Don
are you running a 12 or 14" wheel? i found the 14's got beat up real quick vs the 12's. i run a 26" itp mudlite on my rhino, works good. had the itp terracross on my rhino that got stolen, found those to be a nice trail tire.