I use Zillow Rental Manager and started using it exclusively for one unit I manage that came off a BRRRR and was rented late last year.
I'm using it to collect the rent for this property -- what others have said about waiting 5-6 days is accurate. However, I like the ACH payment aspect and it auto-deducts. This past month it told me it was initiated and would take 6 days, like normal. On day 3 (mind you, 2 days after it was due),I received an e-mail saying me there is insufficient funds and/or a problem making the payment. My PM got on the horn and sorted it out with my tenant (who paid via a different app immediately), but still.
I also think the background services are spotty at best. One tenant that I got close enough to have a county CO pulled for turned up to have warrants locally, but it didn't show up on the Zillow background screen. I can only surmise two things -- one, it was too recent to have appeared in the screen, or two, Zillow only does federal checks and if local agencies are not reporting up, you won't know. Turns out the county CO saved the bacon, so to speak.
Loved the listing and application aspects, though. I received good information and good leads and I'd say its easily worth the money they charge. I think many renters are using Zillow to check for available rentals, so it makes sense. I also use Facebook Marketplace but it seems like FB is 97% tire kickers. I have canned messages for everything in response just to make my life easier.