never used a wright stander, but have used John Deere 657 52". What rivablaster701 says is true. The standers are much easier on your body, you can roll with the machine, use your legs as springs when you see pot holes or whatever, you have much better vision compared to the Scag sit down I've used.
On the sit down it is harder to see potholes, you can't really brace against them, If your seat springs dont absorb it your spine does.
The sitters are often quite a bit faster though. Both good and bad. You can get done quicker, but hitting that bump at 10mph sure makes the chiropractor smile. Also the sitters usually weigh more which means more load / rutting potential and the bigger tires are a lot more expensive to replace.