I echo everything you say Willard, but having just got the 35hp Rayco I'm happy with the extra power.
One downside is the manoevrabilty, that old three wheel design can go round the tightest of spaces. Plus it's weight means you can get it out of a hole with a bit of elbow grease and swearing. The same cannot be said of the 800odd kg Rayco.
I see now why 4wd is handy on these machines.