I recently completed my PhD and now I looking for my first postdoc. Right now I'm in a terrible situation.
During my PhD, I had the possibility to join a great research group in the US and before to leave, the PI asked me to come back for a postdoc. He was a great mentor and I really would work with him again, because I'm interested in his research line (totally different from my education). I thought about it a lot, and I decided to go! So I called him to get more information, but he told me that had had a great opportunity at NCI in another city and decided to relocate the lab there, but he said that if I wanted to go with him he would be happy! Since he must officially sign in May and we talked in February, he suggested to me to do other application as well. Then we talked again in March, and he told me he could start the application process on May. In the meantime, I did others applications. I had a good feedback and one of these already sent me the official offer. I'm evaluating this offer, but I really want to work with the PI that I already know and admire.
What do you suggest? What I could say to the PI that I waiting for? I'd very much appreciate your opinion and reflection on this topic.