Today I tried to wear a Valve Index for as much of the workday as possible. Programming, web browsing, and just seeing how long I could go for. It started out not-so-great but improved drastically as time went on.
Let's compare comfort wise to the Vive + DAS. Both start out completely comfortable & degrade from there as time goes on. Vive + DAS takes 10 minutes to start to get uncomfortable, then in another 30 or so it's agonizing. Index, on the other hand does something interesting: after about 10 minutes it also stops being 100% comfy, but that dip is just barely enough to register as 'not completely comfortable.' There's a slight pressure on your cheeks that will wax and wane, but it took almost 5 hours for the next major discomfort milestone to pop up.
To summarize, this is a viable work machine. It's not yet at the perfect ideal of being able to live inside VR, but it is quite the impressive milestone towards that goal.
The Valve Index is a great VR headset, however like most VR headsets.. it comes with pros and cons.
I recommend the Index to someone who wants to get into roomscale VR. If you want to be able to sit down and enjoy VR, then it might be better to get something like a Samsung Odyssey.
My Index arrived today and I'm loving it so far! I do wish that Valve would've released an in-game to go with the Index launch. At this moment there is almost no content.
If you are looking for a high end VR headset the Index is currently the best option. You can see my first impressions here https://youtu.be/lyOzivZEBs0