WordPress.com websites are free, much easier to setup and has secured login (SSL). This provides limited control when coming to theme selection, installing plugins or widgets. The lack of capability to embed custom code is one common complaint I hear from realtors as evident from this Zillow discussion.

On the other hand, WordPress.org will cost you. You need to install and maintain the software yourself. At the same time this provides you maximum control if you have the technical capability. Here are more details on the differences.

In my opinion, there is no reason for a commercial website to run on WordPress.com. I will be interested in hearing from the readers. What do you think?