>>388893947
Yes/no, depends on you. 
The index is overkill for most VR gamers. If you're not doing room scale there's no reason at all you should have anything more expensive than a Quest 2. 
If you are.looking for room scale, the Valve Index is a top tier setup and $700 is a low price for it. You can probably resell in a few years for $300-$500 if you keep it in good condition