I've been using a really old Dualshock 4. It was fine for modern, but I have switched to classic recently, and getting some inputs has been really difficult. The dpad is really mushy. Many times, I'm positive I'm holding down back but still end up getting hit because the controller doesn't register the input as down back, it's really frustrating. I love everything else about the controller, the button placement and the size suits my small hands really well.
Looking around I found some old threads where people were praising xbox controller but then I found this video and now I am not sure, the face buttons also seem really stiff. Other pads like HORI and Razer ones are way too expensive here so either I just buy a new DS4 and hope it'll diminish my issues or buy the xbox controller.
In my experience the playstation has always had a better dpad for fighters than the Xbox. I'd even say that the worst first party playstation controllers are better than the best Xbox controllers for fighters but I haven't tried the series controller yet so maybe they finally made something that's not terrible for fighters.