Looks like no one has been then
Avoid the hurricane season, especially Sept & Oct, careful in all countries especially Guatemala, Honduras & El Salvador where violence is high a lot due to Mexican drug cartels moving in. But having said that they are great places to visit as is Nicaragua - which is the least developed. Depends a bit what budget & interests are. Costa Rica is by far most developed toursit wise and safest - but full of american tourists.
Mexico City!!
Nicaragua is a troubled country. A very good friend of mine (from my time in Italy) was murdered there in 2003.
PeaceReporter - A life for Nicaragua