Pros- Helps make hooking up attachments a little easier.
You can adjust the angle of attachments on the fly to make them work much better. (especially a box blade)
I could lift my brushmower higher, back into heavy brush and drop the mower when clearing my property.
I use my hydraulic top link nearly every time I use the tractor. I wouldn't be without one.
Cons- Other than initial cost to install it there are no cons.