With Hillman, it depends on if you are discussing the old standby model or the new "deluxe" models that are basically the same as GKS. The advantage of GKS over typical toe jacks like the original Hillman is the ability to easily change gross positioning of the toe, swivel counterbalance feet, toe is only 5/8" thick (5 ton model anyway) and swivel feet are tapered for getting under tight spaces, connection for remote pump if needed, extending pump arm, hydraulics moving the toe assembly on ways rather than the hydraulic ram and wheels to move it around on (when the pump handle is extended to push and guide it). But all this comes at a price, so depends on how often you need one, how important gross toe positioning is, and how cheap you are.
For my often awkward situations I can't stress enough how useful the tapered swivel feet are.....sometime I can only get one of the feet in position temporarily to raise the machine just enough to then lower it on timber and get both feet under for the final raise for example. Also when you have remote pump possibility you can have two jacks raising one end of a wide machine base where you pump one jack with the standard pump and pump the other one with the remote pump located inches away...and lower the same way....except you have a nice large knob to turn for lowering in a very controlled manner, instead of inserting a cheap tube into what is really just a Chinese bottle jack.