I bought a new 84" rhino a couple of years ago. Price was $1800 but traded in a 72" rhino for $1200. (Bought the used 72" rhino on an auction for $700 the year earlier but didn't like the side discharge). When talking to the dealer about the trade in on my 72" rhino mower, he said it would be $600. I said, I was hoping for a little higher. He gave me a puzzled look and said "You want to pay more?" Then I realized he was telling me I would have to pay $600 difference with the trade in. I stammered a bit and then told he I misunderstood what he said. I promptly agreed to deal!
From what I have heard, I believe a new 84" rhino will be considerably higher. My 84" rhino was the welded deck model. The latest models use a pressed deck. I prefer welded decks over pressed decks but otherwise they look about the same.
I would definitely recommend a rear discharge deck, especially in the larger decks. The dispersal of the clippings is much better with my 84" rear discharge than my prior 72" side discharge.
I also have a 90" bobcat mower from the front of my TC. It mows similar to the 84" Rhino but easier to manuever because I don't have to look back.