SAFETY
Acapulco has seen more then it's share of violence from early 2010 through November 2011 when the government took steps to eradicate the problem. Since the implementation of operation Guererro all crime especially violent crime has been reduced over 95% and the operation is due to continue through the winter of 2012. The state department still has many warnings throughout the region and will likely keep them in place for many more months. Yearly travelers to this city have reported no issues in the way of safety and are reporting this on a daily basis on the trip advisor forum.
More often than not, the types of common crimes that do occur in Acapulco are crimes of opportunity - mostly petty theft. Travelers are well-advised to safeguard their belongings when they're at the beach, not to leave their personal items unattended when they enter a pool or swim in the bay, and not to flash either their cash or expensive jewelry when walking around the city. Pay attention to those admonishments and you'll not likely come up against any problem.
The personal security issues in Mexico, including Acapulco, is affected by the long-standing general distrust of law enforcement officials. Overall, the police are considered to be untrustworthy. If you're victimized, however, do make an effort to report the crime to the police and to the local consulate of your home country (or your embassy in Mexico City, via email).
For the most part, Acapulco is a safe and enjoyable destination. Always be aware of your surroundings and the people around you (sage advice, no matter where one might be traveling to), and you should have a memorable visit.
HEALTH
Given that the climate in Acapulco is typically hot and humid, travelers should check with their own physician - prior to a trip - with regard to any precautions they should take during their visit. Bring plenty of good sunscreen or sunblock and a favorite brand of tanning lotion, as the Acapulco sun is very strong - and it can be costly to purchase these items on arrival, even worse if you don't use them at all. Be cautious when patronizing food vendors on the street or on the beach, because some of the items may not have been properly stored, refrigerated, cleaned, or prepared. It's always 'best' to drink bottled purified water - and only drink ice cubes made from purified water. Take some precaution, particularly during the summer/rainy season, to protect yourself from mosquitoes - as dengue fever is a concern along the Pacific coast area where Acapulco is located. When on vacation, some travelers tend to leave common sense behind; bring it with you and use it - and you should be fine.