thank you both. i'll try the side discharge and see if anything improves. you are correct in that there is a ton of accumulated clippings under the deck but i clean it out every use (i hoist the front after each mow and it is normally caked with clippings).
i had a similar thought on the hardware store ZTR's - they dont seem much of an upgrade if you dont need the tight cornering. if i was going to switch i would pick up a moderately used commercial unit. exmarks seem to be popular with landscapers here and there are lightly used models available in the $3.5 - 4.5k range which seems reasonable.
i'll try the side discharge next weekend and report back - thanks again for the help.