Appfolio requires at least 50 doors.Buildium is great for self-managing and a small number of 3rd parties.Propertyware and RentManager are for 3d party managers that want customizable software.

It includes a web site and is very customizable.

Very powerful and customizable. 

Makes everything very easy from creating a single listing that syndicates the property on multiple rental websites, screening tenants automatically, creating a state specific and customizable leases, e-signing the lease, having your own web address if you'd like for your properties, and setting up electronic payments.

The leases are customizable so you can make them exactly what you want. 

For example, our clients are provided with a  customizable bookkeeping template optimized for rental real estate.

I'm actually not only a Real Estate Investor and Broker, I am a Salesforce Developer and have customized Salesforce for the specific way I do business.It is extremely customize-able, expandable and has a lot to offer if you were to develop your expertise in the platform.It's really not just a CRM.

Very durable and customizable but there are a lot of subtle nuances.

It's very customize-able.   

Both the pre-qualification and application forms are customizable, so these can be adjusted to fit your specific needs.As for support, this is incredibly valuable to hear.