Yes I have a simlar Quest/Reverb combo, both fulfil different needs. Just sold my Pimax 5K+ on Ebay. To be fair to Pimax they did push the bounderies and tried something other companies didn't/couldn't do e.g. 170 FOV, however both the Quest and the Reverb are so well constructed and offered something a little better. For me Quest for roomscale (you can't beat wireless), and Reverb for seated experiences (clarity is awesome)...so over to you Valve Index.
Some very quick first impressions and that's without experimenting with Super-sampling.