>>272110692
I wouldn't expect a next gen headset before 2021.
Rift S is a good entry level headset. Easy setup, cheaper than the Index, easy access to exclusives, not a lot of hardware issues.
Index is a better headset with a better refresh rate, better tracking, better fov, higher resolution, less SDE, and finger tracking. It's hard to say it's necessary $600 better though, and early units have been having a lot of QC issues [spoiler]although mine has been fine so far[/spoiler]. It's kinda hard to recommend unless you're sure you're going to spend a lot of time in VR.