I have been in the field of property management for the past 7 years and no one has ever asked me if I had certification. As soon as I mention I have a business degree and so many years of experience and what I have done that is enough to give them confidence. Many clients would not even know what a CPM is if they saw the abbreviations on your card. Any designation is good but I don't think it will change how successful you can become. I believe if you do not have a degree then it will be more helpful for you, however, you must manage so many properties at a time in order to become a candidate and do so for some time, I think it is around 100 for residential so it is a catch 22. Definitely make sure to have your real estate license if you don't already. In most states you must have it if you are to manage multiple properties that are different owners.