I have both, LINX in my YJ and the factory AUX switches in my Gladiator.
Honestly, it depends on what you are going to control using LINX. If you have lots of ARB products, then LINX is the way to go and obviously messes well with ARB products and offers automation features on some of the ARB products. On my YJ LINX controls my air compressor with a pressure control system (shuts off at the pressure you tell it when filling tires), front and rear Air Lockers, monitors my fridge (you can control the newer ARB fridges with it), reverse lights, rock lights, and Intensity Solis. You can dim the Solis lights with LINX.
Since I ordered my Gladiator with the AUX switches, I use it to control my front and rear Air Lockers, and compressor and send a 12v signal to my REDARC system in the camper. I was actually going to install a LINX in my camper to control all the camper accessories, but they were way back ordered when I was outfitting the camper so I went with a SwitchPro.
Lastly, the only real drawback of the LINX is to plan for a day of installation depending on what you wiring up. Because it will run several systems, wiring can be a bit tedious, so make sure you run all the wiring even for modules that you are using right now to a general location to tap into in for future installs.
Let me know if you have any questions. I worked at ARB for 18 years and still a beta tester for the LINX system.