CSTE is not very valueable. My opinion was based on last year experience. They are not very organized and has very little direction towards certification. If you want a certification that is valuable then go for CSQE and later go for PMP.
In case of CSTE there is no mandatory requirement to get training from QAI first. It means that CSTE is independent certification.
In case of CSTP there is a mandatory requirement to get IIST training first. It means that CSTP could not be considered as an independent certification. I would prefer to describe CSTP as a certificate of successful completion of IIST courses.