A few years ago, I spent about $1200 for the SHRM Certification Preparation course and for the exam. I passed the exam easily and regretted spending the money for the certification class. The test was simple multiple choice and required very little rote memorization. The certification was a nice additional bullet point on my resume and I am sure it has helped me receive interviews that led to my current HR management position with a Fortune 10 multi-national.
However, the content and curriculum that led to my certification are not well designed and unlike other professional exams, CPA, BAR exam, PRO-E, etc. the certification is really not a well-respected credential across industries. The primary value of the certification is a signal to the marketplace that you are ambitious and have a desire to improve yourself and to continually pursue self-development. That type of signal is very powerful when being recruited or when seeking a promotion internally.
I especially recommend certification for HR professionals who lack an undergraduate education or who have not formally studied HR. Again, this certification signals an attempt to compensate for a previous lack of education or training.
For those who have greater long term aspirations I recommend pursuing a graduate degree, specializing in Human Resources or Business Administration. The return on investment on a degree from a legitimate educational institution is remarkable. In a previous post I have provided rankings of the top HR graduate schools. Aspiring HR executives need to pay the price academically as well as with deep and broad HR experiences.