For those that have tried subwoofers in their systems and didn't like them, the usual reason for this is improper placement and integration. They can take quite a while to set up properly and incremental changes can yield great results but could also make a mess of things. Any easy was to visualize what is happening in the setup is to use a laptop and REW, Room EQ Wizard. It's been around for many years and is quite a helpful tool in subwoofer setup.
Keep in mind that without knowing how your particular room reacts with bass and your seating position, you could be chasing your tail for weeks or longer growing more and more frustrated with the setup experience. In our last house, I spent a whole weekend setting up 2 subs in our family room, running dozens and dozens of sweeps in REW, each time altering settings in the preamp or the phase settings on the subwoofers, or the physical locations of the subs, volume settings, etc., etc. to get it right. But once I had that done, with the subs properly married to the system and the room, it was fantastic. You just can't plop a subwoofer or subwoofers down any old place in your room and expect good results. Patience is key to unlocking what they can do for you.