The Rubicon actually came in 2001, 2 years before the Rincon.
The Rubicon's trans is like the hydrostatic trans in a lawn tractor.
The 400AT had a very similar transmission, but lacked low gear, weren't very good.
Pro's: Most durable of all Honda transmissions, smooth shifting, more efficient than the Rubicons trans.
Cons: Geared high, poor engine braking.
Pro's: Very smooth, lowest geared of all the Honda transmissions, "best" suited auto for work.
Cons: Sucks up power, unserviceable, expensive to replace, 01-04 Rubicons were guaranteed to have a Hondamatic Failure, it wasn't if, it was when.
Pro's: Smooth shifting
Con's: Unserviceable, prone to failure. No low gear and small motor make the bike completely gutless. Good bike for the wife to ride.
New 420AT? Honestly can't say too much about them, no real experience, never ridden one. Have heard they are geared high as well.