I only own Index controllers, not the headset. I have a mixed tracking Pico 4 setup and wireless functionality is definitely one of the pluses; the higher resolution panels also make a significant difference (the Frame and the Pico 4 seem to have the same resolution). This is basically an open Steam-backed Pico 4 that's superior to my hardware and definitely superior to the Index. Here's a comparison:

https://vr-compare.com/compare?h1=0jLuwg808-j&h2=w8xCM-oPA

The 1000hz tracking frequency is from the Lighthouse tracking system, which the Frame loses. For that and other reasons, I am not convinced the controllers are better than the Index controllers. Personally I think it's likely I will keep using the Index controllers, since I have the whole lighthouse setup and I own trackers as well.

Wireless, weight, no lighthouses, standalone use, more polished rendering. It won't be prefect, but it'll be a heck of a lot better experience than what came before.