again it depends on what you are comfortable with. that can be negotiated, mine is not 15 years. I would say the shorter the better so I would at least negotiate it. Even after your contract is up you may decide to continue with them anyways.
It seems the SIAA is very very slow in responding to the email/calls. Do you have the same concern with them? I have not yet signed up with them, and may go somewhere else (Suerior Access may be)