I've tried a few other services for my properties, but the UI tends to be really sloppy for other "apply online" web services. You need to make it easy for me to use and inviting for my potential tenants.
One thing that would make me almost certain to try it is if you could bundle an affordable credit check into the application process. Any plans for something like that?
I'd be interested in helping beta test this if you have a need for that.