It depends on your current situation.
The better choice is to have a blog on wp.org.
But I myself use WordPress.com
Because my situation is matching with wp.com.
I want to read, write, and connect. instead of wasting time by setting up my self hosted site.
I will launch a self-hosted and I did but found no use.
If you are hoping big from your blog and want to build a blog as other top bloggers have then the better choice is wp.org.
If you just want to get your message out and connect first with others then wp.com is the best to save you time and energy.