Excélsior has some polling that measures Obama's post-visit shine in Mexico. Seventy-eight percent of the respondents expressed a good or excellent opinion of him, 65 percent said that his stay in Mexico was different than previous official visits, 58 percent said that it shows a change in interest from the US toward Mexico, while 74 percent said it marks a new era in the relationship. The response was not quite so overwhelming when the questions did not focus on Obama but rather the US as a whole: 35 percent think the relationship between the two nations has improved, against 52 percent say it is the same as always. (This does represent an increase of 15 points for the latter position.) Only 31 percent expressed confidence in the US, compared to 31 who showed indifference, and 32 who said their feeling was one of distrust.
These polls are fun, but given that the results are all over the map and it is still a very fresh memory, I don't think we can draw any lasting conclusions yet.