Imo the Valve Index is the best. It's the market leader in terms of games through Steam, and has really good tech that works well and should last a long time. Oculus is made by facebook and requires a Facebook account to use, hence why its 'cheaper' as then the user is the product again. The tech is not as good as the Valve Index either. The Valve Index is very expensive by comparison though! There are VR subreddits on Reddit which are full of people giving advice and sharing reviews so worth reading up over there.