The Sense moderators and product marketing have the ability to do surveys and frequently use them when they do product planning. For instance, they hosted a solar survey before developing and rolling out the most recent solar features.
As for time to (first and next, …) detection, Sense probably have a very accurate view on this since already have the detailed data on detections. A few of us users have done the analysis here, although it’s more difficult to measure than you might think, unless you are accurately logging when new devices are actually added to the house…
As for the breaker box question, I suspect the type of breaker box plays a very minimal role in Sense “signal” noise - much more a function of other devices you have in the household. And surveying breaker boxes might be more complicated than it seems - I have 3 Square D breaker boxes in my house (1 main with 2 subs), populated with mostly Square D breakers, but a few other brands as well, with a solar backfeed breaker in my main panel. I’m betting that the topology of my main box WRT the subs and backfeed have greater effect on Sense “noise” than the make of the breaker box.