UI is the easy part. The listings that are accurate, honest and up to date are hard. Do you want to become a real estate company as well, hire your own agents, pick up the phones, take customers for the visits and so on? Or you need to provide a service that these companies (and some landlords, perhaps) want to use, in the right way.

Why would they give you out the exact address? A competing real estate company (not one, three, more) would immediately contact the landlord and offer him a better deal. Why would you list the price correctly, if you can hide some additional fees in the comment, stay 'technically' correct and look more attractive in the search?

I work on a service like this, we are quite rich (well, as a company, I'm just an employee), but we really can't do what you want. I'd like to, I don't like to use the service much, it's not bad itself, but it doesn't help you from dealing with the real estate agents and if I say that they are all liars and frauds, I'm not exaggerating at all.

(But we're in eastern Europe, things are perhaps different in America.)