1. Rift S has less screen door effect as it uses a different (better) pixel arrangement, however it has worse colors and cannot show true blacks like Quest can (OLED panel inside)
2. Rift S has a 5th camera for inside tracking which can/does help increase tracking range. That being said, I'd say Quest works really well and I do not feel the need for 5th camera.
3. Rift S is much more comfortable, if you get a Quest you can solve the comfort by putting a counterweight on the end of the strap, the change in comfort is incredible.
4. Some people report that they can feel a slight latency when using Link with Quest (some don't feel it)
5. Rift S has a slightly better refresh rate (80Hz vs 72Hz)
6. Quest has beta for hand tracking (using your real life hands in VR without a controller), it works decently and will open up new kind of experiences. Rift S apparently won't get this feature to keep compatability with Rift.
7. It looks like Oculus is focusing on Quest for the future, I wouldn't be surprised if their main headset in the future is "Quest" like rather than Rift like.
8. Quest can be used untethered. This is for me the killer feature for VR and when you start using it, it really makes a big difference. One caveat is that I do not have a "pulley" system so when I am tethered, the cable is always around and intrusive. You can even use Quest untethered for PCVR content by using a 5Ghz network and Virtual Desktop or ALVR (probably officially via Link in the future)
9. Quest with using Link is more performance intensive as it needs to encode the image and send it over the wire to the headset, Rift on the other hand just passes the image via cable to the display in the headset.
All of this being said, I'd say that for the vast majority of users, Oculus Quest is the headset to get. It allows you so much flexibility and capability that it is hard to advise against it. Lot of people think that being standalone is not a big thing for them, but when they get the Quest they realize they can use the Quest in the living room, on the porch, take it with them when they travel or as a party tool.