Having worked with different OC spray devices over the years, and being quite vocal in my recommendation to carry OC spray even (especially) if you are a gun carrier, I am always experimenting with these options. I recently picked up a few of the POM units and, like many who have moved to it, I am particularly fond of the size of the package. The POM is significantly smaller than the Sabre Red MK6, which I long considered the best stream pattern OC device. The POM unit performs almost as well with range yet is much smaller and easier to carry. I think it is the obvious choice now for those who want a stream pattern spray.
Which leads me to the fact that I have, for a long time, carried an ASP Key Defender as my pepper spray of choice. The Key Defender is a robust device that doubles as a striking implement and shoots a cone pattern of spray. The basic difference between the POM unit and the Key Defender is this: POM has further range, is less influenced by the wind, and has considerably more liquid payload, but the Key Defender facilitates much easier placement of the spray on the face at close range due to the wide cone pattern. Therefore, choosing between the two is a matter of determining your priorities.
Do you want to be able to more easily hit the face with the spray? If so, the key defender is as easy as it gets. The large cone pattern that it emits makes dousing the face of the appointment with a lot of spray easy out to about six feet. However, if doing this outside where there is wind, it is easy to self-contaminate with the ASP units. The wide cone pattern of aerosol particles makes the pattern very easy to hit the target area with, but also contributes to a high chance of self-contamination.
The POM unit, and similar stream devices, provide further range, I would say a good ten feet, but you must “walk” the stream into the face at longer distances, like you would if spraying someone with a hose. It is, quite frankly, much harder to get good coverage on the face compared to a cone pattern spray. However, there is no denying that self-contamination, or the contamination of others in the environment, is much less likely. The stream pattern is quite resilient against the wind. Additionally, I found that the ASP Key Defender provides only 5-6 half-second bursts. The POM delivers 15-20 half-second bursts based on my testing.
Go with your preference based on your priorities and your own experimentation. I highly recommend both the POM OC unit and the ASP Key Defender. With that said, I have moved to the POM unit myself, as I like the wind resistance of the stream pattern along with the much higher amount of spray on tap compared to the Key Defender.