In my minds eye it could allow for collective resources to compete with the functionality and easy user interface of Zillow.

I began with Podio, but I didn't like the interface.

Besides the glitches when I was using their interface, the dealbreaker for me was the fact that you’re stuck with their leases if you want to use their e-signing.

Make sure you get a feel for what their documentation and interface look like. 

They should be the point person for the collection of rent (if that's your procedure), report utility problems, interface with a customer or two to sell or rent a vacant home or lot, pick up litter if possible, meet with residents on rules violations occasionally, tell you if the mower or a contractor showed up as promised.

I also use Ally for the ease of their interface, a fairly decent interest rate, and high transfer limits. 

It automates text and mail campaigns with a sleek and simple user interface. 

It's free to use and has a good interface.

Sounds like by contractor you mean, you did a contract between an external person and your PM company so they can interface with tenants on your behalf?

A little bit about me:Growing up my parents had a summer rental on the cape that I rented out to weekly renters, so I've gotten pretty good with professional interfacing with renters, that's how I know I'm ready to make this step...