I normally decide on the following points:
1. Reputation of the Organization ( It is difficult to find out as they are so many new are coming)
2. If Training a mandatory or self study i permitted? I just drop teh idea of any certification, which makes the training mandatory. You can not beat teh experience by 1 week training.
3. Price ( If price is more that $150, I am sure to see the market value of the certification and how famous the certification is)
4. Recertification requirement: i normaly choose the one with no certification requirement unless tteh certificate is very famous (CISSP, CISA). one which does have the recertification requirement and with hafety recertification fee, avoid.
Please coment or add to the list.