I did my CPL in Florida and I have a job.
If you are asking if there is any legal reason why a JAA CPL course undetaken in the US is less valuable than one undertaken anywhere else then the answer is no.
If you are asking about where/how you should train to maximise your chances of getting a job then there is a LOT of information on here to help you make a decision - make a mug of tea, sit down and do a lot of searching here - most of your questions will be answered!