I may have not been totally clear in my first post.
I know that the 3320 has a better loader and 3ph.
I was just trying to get an understanding of why the OP was disappointed with the 790.If it is because of an underpowered loader and he does a lot of loader work, then yes a 3320 would be a big improvement.
But if it is the general size of the tractor, there isn't much difference, since they are about the same in physical size.When it comes to mowing, bush-hogging, back blading, pushing snow, pulling logs, there isnt enough of a difference, for me anyway, to justify the cost difference.
I was more interested in why he was wanting to trade up, as to better offer suggestions for his situation.