I've had no tracking issues with the controllers in a bunch of the demos I've tried so far. Maybe I've gotten lucky. I'm planning on buying a few more games like Pirate Trainer or SuperHot to test with this weekend. That should test the controller tracking.
Text may not be as crisp as my 32" 2560x1440 monitor, but it's readable and becomes sharper when I put it in the center of my focus.
All in all, pretty happy so far.
I am very happy with it so far in Elite - it is a jump in resolution and SDE reduction! I can still see the SDE, when I go out of my way to look for it.
But I have had tracking issues in other games (not at all in Elite).
In Arizona Sunshine when you are in the pitch black of the mines holding your controller up near you face as its a flashlight in game I will sometimes lose tracking - just in time for the zombies to attack. Its simple to get back as I just lower it to where my headvisor can see it. When I decide to go all "John Woo" in a shooter and hold my guns out in a V pattern shooting left and right and look down the sight of either weapon, I will lose tracking on the other until I bring my arms in closer or stop firing like an idiot.
None of its bad and I am playing other games for fun so I am not so competitive that some tracking problems that are minor don't bother me.
But none at all in Elite.
This weekend I drug my PC over to a friends house as he has a Vive and we wanted to do inperson VR COOP. Two things I noticed right away. The O+ is certainly more high res than the Vive, as the Vive SDE jumped out at me immediately. (although the Vive did appear somewhat more 'sharp' - hard to describe, due to the O+ SDE smoothing - Still I will take the O+ all the way).
I could transport my VR headset easily as its only one USB, one HDMI and two controllers with no base stations. So if you plan to ever move your rig, with the O+ its simple.