Rift S is more comfortable, but is lower resolution, and is no longer actively supported. It is however a native PC headset so less faffing about than a Quest 2 which requires an additional USB cable (which can be expensive) and an add-on headstrap.
Personally though I'd go for the Quest 2 simply because going forward that's where all the support is going, plus it's also a standalone device with a higher resolution.
Another thing to consider is Rift S has a fixed IPD but Quest 2 has a partially adjustable IPD.