From my experience, MeterHero is both legit and trust-worthy. I signed up this spring, and so far they’ve deposited $57.67 into my PayPal account. When I’ve noticed data seemed to be incorrect, they have quickly researched and made corrections. The only real work on my part (no fault of MeterHero) is that I have to send in a PDF copy of my water bill for them to manually input. This is due to the fact that my water company has no online billing capacity.
So, those are my anecdotal but real-live observations.
Edit for PS: I see that Rachio is the featured sponsor on the MeterHero site. Seems like a good fit.