If you are going with a 3pt hitch mower, some sort of flexible upper link is a plus. If the upper link of the 3pt is rigid, as the rear wheel moves up and down over terrain it has to lift the entire mower. If there is flexibility in the upper link, either through the tractor top link or the linkage going back to the mower, the rear wheel can follow ground contour and the lower links of the 3pt will keep the front of the mower at the proper level.
If you are planning on using a quick hitch attachment system, be advised that not all mowers will work properly with one. Without going into detail, the flexible upper link needs to be part of the mower hitch mechanism if you are going to use a quick hitch. I've had to do some modifications to various machines but finally have everything I use on my 3038E quick hitch friendly. Makes hookup a lot easier. The easier it is to change implements, the more likely you are to change them for small jobs. Or at least that is the way it works for me.
i have a 3038e also with a quick hitch. the hydraulic top link makes it a totally different machine. i have never heard of a flexible toplink. i have heard of people using a chain instead of toplink, but there have been deaths because of it. the cutter has nothing to hold it down and supposedly can fly up and kill the operator.
