The sites you listed are all braindump sites that are unethical and an insult to people who study hard and actually work for their certification. Also if you're caught using them Juniper will revoke your Certification and you will be ineligble for any future certs with them.

Any site that basically offers you PDFS with tons of questions from the tests and the answers should be avoided by any ethical professional. If you want to check whether a site is legit or not I recommend checking out www.certguard.org