I recently bought Arizona Sunshine, Pavlov VR, Sairento, Diner Duo, and Knockout League.
Knockout League is really fun. It's mentally and physically challenging. Tip: Stretch before playing.
I was hoping to play AZ Sunshine with trackpad locomotion, but the inputs were acting strange.
I found a mention of it on the Steam forums, so at least I know I'm not alone. But for now, I'm taking my $40 back.
I revisited Quell 4D to finally try
their touchpad locomotion, and wow, night and day. Really good except for it sometimes not registering left and right. It seemed if I lowed my thumb onto a side direction, it wouldn't detect it, but if I put my thumb in the center and slid it out like an imaginary thumbstick, it was fine. Maybe it's a software bug, a hardware issue, or an intended behavior.
Either way, future Vive controllers could benefit from having light tactile markings in the center, or even analog sticks. I know there are games that kind of require touchpads by design, but that doesn't mean hardware redesigns can't happen.