I don't think this can be said enough times...
IMO...If you have a tractor that has hydraulics...and you do any type of earth work /grading...(tilling included)...a (true) hydraulic top link is the absolute best (equipment improving) investment an operator can make...a side link is second only because I am addressing a thread about top links...
...in a lot of conditions (IMO) a hydraulic side link is even more an improvement...when it comes to being able to use attachments and end up with professional looking results in a relative time frame...!
I am planning to install a hydraulic link, but I have Pats attachment which extends the lift arms couple of inches. So it looks I have to get the longer one cat 2. The only disadvantage that I can see with a HL is that you have to keep the tractor running to hookup the implement but I guess that is not a biggie.