So, I setup the Index Controllers, and I'll admit that the setup can be a bit... wonky. On the other hand, it's probably far, far simpler if you're just setting up a brand new Index. I normally charge my controllers with the default cables plugged into my computer, and when trying to pair, I left the Vive Wands plugged in. Unfortunately, this seemed to cause a problem as one controller crept back in after I paired both Index controllers. After detaching both controllers, I no longer had any pairing issues.
I'm a little mixed on Beat Saber with the Index Controllers. I'm not 100% sure if the saber position has been refined to work with the different grip on the Index Controllers. I used a mod called SaberTailor and some values found online to adjust the saber's position to help make it a bit better. What really makes a difference is how you don't really move your wrist much with the Index Controllers, which causes you to put a lot more strain on your arms.
You'll see this same sort of "weird aiming" when you're using the controllers to select items from the Steam menus. Both controllers create their "selection laser" from the front of the controller, but the difference is that the Vive Wands sort of emulate a flashlight. On the other hand, the Index Controllers feel more like a blow torch where it's at a 90-degree angle.
I also made sure to try out Moss, but I ran into a bit of a snafu. The first time I played it, it kept using the Vive Wand configuration. If you go under controls, it will show you which control scheme you're currently using, but there's no option to change it. I'm not sure what fixed it, but the second time I played, it was showing the correct control scheme. Although, in regard to controlling Moss, it is worth noting that the thumbsticks might not be in the best position on the Index Controllers. It's a bit subtle, but there's just slightly too far to the side. So, you end up moving your thumb a bit further than you'd like to use it.
I haven't really tried out the grips in much other than the Vive Home app, but the finger tracking seems to work fairly well. To be clear, it won't be as good as some crazy, accurate glove-based apparatus, but for what it is, it works fairly well. Although, given that I'd prefer to see the Index Controller's control scheme made far more common, I do wish that they'd develop a touchless version that retailed for significantly less. I think this would work the best given how similar the Index Controllers are to the Oculus Touch controllers.
Negative, I just have the standard HTC Vive headset. I haven't even tried out the wireless or the Index controllers I have now too yet. I'm a gaming failure. fml
My only complaint about the Wireless is that even though it's an official add-on, it still feels about as tacked on as the TPCast version did. You still have to launch an extra piece of software before playing VR and you have to wear that goofy receiver on your head. I guess it doesn't help that I think we pushed toward gaming being "simpler" over the years, so tacked-on add-ons always feel a little hokey.
Oh, and you may want to be a little wary... some users complained about excessive heat coming from the receiver when using it with the original Vive.