In my experience sadly few people really check its presence. Sure, there might be an aggressive spam filter in place that collects these mails. But this protect

In my experience sadly few people really check its presence. Sure, there might be an aggressive spam filter in place that collects these mails. But this protection will almost always be removed once a customer or supplier couldn't contact you. DKIM isn't hard to manage, SPF can be a pita. Although IP blocks are a very sensible network management tool (cloud provider and customers hate it), it is more difficult to administrate than setting up some domain keys. It will have to be managed whenever anything that is sending mail changes its public IP address, which very often happens if you host it in the "cloud".