If you are going to work for a health club after getting certified, it may be best to check with them to see if they care which certifications you have.
The best trainers I have ever had had no certifications at all. They were the guys at the gym who taught all the newbies so that we didn't kill ourselves.
Sadly, today you need a certification to show someone how do do a pulldown
With that being said, there are a lot of crappy cert companies out there. eg -
www.expertrating.com/personal-trainer-certification.asp