Can you help me decide? I need opinions.

I sent my resignation letter to my manager because I felt like they don't see my potentials and they don't value me.

He talked to me and he said that he'd do everything just he could keep me. He said that he values me and he see potentials on me. He gave me a day to think about it.

Last Friday, I already signed a contract to my new employer and they are just waiting for me on when can I start.

My new employer just offered me less than what I expected but they promised me things that I hope they'll give.

Now, I don't know what to do. I need advise.