Is certification from the ASPS as good as ISAPS as an indicator of surgeon proficiency and safety?

Hello and thank you for your question.   The most important credentialing is board certification by the American Board of Plastic Surgery.  To be a full member of ASPS, your surgeon must be board certified by the American Board of Plastic Surgery.  It is very
important that you thoroughly research your surgeon before committing to
surgery. It is a good idea to research your surgeon's educational background,
online reviews, before & after pictures, and speak with anyone who you may
know who has had surgery with that surgeon. During your consultation, make sure
that you don't feel rushed and make sure that you have adequate time with your
surgeon and not just their patient coordinator or nurses. If the majority of
your consultation is spent with someone other than the surgeon, this is usually
not a good sign. The most important aspect is to find a surgeon you are
comfortable with. I recommend that you seek consultation with a qualified
board-certified expert surgeon who can evaluate you in person.
Best wishes and good luck.
Richard G. Reish, M.D.
Harvard-trained plastic surgeon

Being a member of ASPS or ISAPS ensures that your surgeon is board certified, which is one of the most important factors. Furthermore it also means that peer plastic surgeons have vouched for them. Consider ASPS the main society. ASAPS members have a higher concentration of experience in aesthetic procedures.