lenny the storm already passed the yucatan peninsula.. cancun just got some rain.. hit further inland by mahual...
my hubs and i go to playa del carmen twice a year and have been for years... it is NOTHING like cancun....it has a much more mature vibe to it...very safe
raqmrod is correct, la isla de mujeres is beautiful and an easy ferry ride from cancun... if you are interested in going to pdc for the day (HIGHLY recommend), its only about $11 ride there ...
not sure how long you will be in cun, but tulum, puerto morelos, and puerto aventuras are also breathtaking stops in mexico.... xpu-ha, akumal, etc.. i can go on and on...
the people are wonderful, the beaches are breathtaking and the tequila... well lets just say..its ALL GOOD!!