Master branch @ rB5cad004d716d + patch is a huge improvement over what I saw with 3.0 alpha/beta (don't know which version I tried exactly, sorry). It's much more usable this way. I still don't like the "grab the controllers to grab the world" approach, though. It's really nice when you're actually using it, but when you don't use that style of navigation, it requires you to open your hands and let go of the controllers all the time. For a moment I couldn't find out why the sticks didn't work, only to realise they were fighting the "squeeze" controls.

As a final usability remark, it would be super nice if somehow the "Auto Depth" functionality of mouse navigation was to be incorporated into the VR controllers. It would be super nice to have the joysticks speed up & slow down depending on how close you are to your model. Just a thought though -- the above "hands must always be open" issue is way more important to me.

UPDATE: I changed /input/squeeze/value to /input/squeeze/force and that made all the difference. It makes it possible to hold the controllers normally and still use the other controls, solving the issue I described above. Lowering the threshold from 0.8 to 0.5 makes it even nicer, as you can then use a more subtle squeeze.