I am going on the postdoc market this year (mathematics). I am now looking into who I should ask for a letter of recommendation. I think my advisor will give me a good one, and there is another faculty who I think will give me a good letter.
I am trying to decide who I should ask for a third letter. I have been told that it is a good idea to get someone from a different university to write you a letter if you can. There is one person who I think would write me a letter, and I think it would be alright. There is someone else, however, at my university who I think would write me a very good letter based on comments he has made to me and other faculty about me. I do not know which would be better, and was looking for general advice about how much having a LoR from someone from a different institution was.