The charts on this page are from the Ipsos / University of Virginia Center for Politics Poll -- done on February 7th and 8th of a random national sample of 1,004 adults, with a margin of error of 3.5 points.
The top chart shows the percentage respondents would choose to be president right now (if all of them were alive right now). Note that President Barack Obama leads the pack with 31% -- besting even Ronald Reagan (22%) and John F. Kennedy (16%). Those three were the only one to get a double-digit percentage.
Donald Trump finished fourth with 9%. Personally, I think that's far too high for him. Any president on the list (including Richard Nixon) would be a better president than Trump.
In the charts below, respondents were asked to rate each president on a scale of 1(poor) to 10(great). Note that Trump falls far down the list with only a 4.20, While Obama stays high with a 6.15 -- bested only by Kennedy with a 6.56 and Reagan with a 6.29.
The only problem I have with the list is the rating of Lyndon Johnson. I would have rated him much higher for his creation of Medicare and his War on Poverty. I guess that most people only remember his mistakes in Vietnam.