>>320607662
Only downside to upgrading to an Index from a CV1 is the godrays and the controllers being almost a downgrade, but more like a sidegrade. 
There's a lot of upsides to upgrading though. Much better FOV and adjustable FOV, resolution, better tracking, comfort, privacy, mic, headphones, refresh rate, better IPD adjustment, can use more base stations, lack of screen door effect, native tracker support. I'm probably missing some