>>324341160
The index is the best choice if money is no object.
The main issue is in fact that the pc needed to run it should be pretty good, and you need to use lighthouse going forward. 
The Quest 2, however, has the same if not better visual quality and spatial tracking, is lighter, is 1/3 the cost for 3 pt tracking and runs PC VR just wonderfully over Virtual Desktop and a wifi 6 router. 
The cable setup from facebook, however, is complete garbage. Only virtual desktop and 802.11AX make the quest 2 a great experience, and you need a decent pc that can encode 4k video faster than 90fps and with less than 1-3ms latency. 

There is currently no "best purchase" vr setup. 
The devices with amazing FOV are worse in every other way, 
The one combination I might recommend over the index is a Vive Pro or Cosmos Elite plus a set of knuckles. 
The issue with going quest 2, as nice as it is, is the cost to go full body later. 
that being said https://twitter.com/HaritoraVR is a good alternative to vive trackers and lighthouse, but it's not widely available.