I am certainly against the idea of an invitation where peer pressure is used to generate a public profession of faith, i.e. the close of a Billy Graham crusade. No one is saved by a public profession, it is meaningless. What matters is if God credits your faith as righteousness. If He does, you are saved with or without a public profession, an immersion in water, or any other "works" thought necessary for salvation. Most of us here trust in faith alone.
While the "sinner's prayer" might explain to someone seeking salvation what scripture teaches, in no way does it generate its own "all in for Christ" commitment in the core of our soul.