While pressure treated wood will help prevent damage due to termites, rot and decay, it   does have its drawbacks.  Pressure treated lumber is treated with a water based chemical that leaves the wood with a very high moisture content.  Some cracks, warps, splits and twists will occur in the drying process; however, these imperfections will not be structural and purely aesthetic.  It’s important to maintain a good coat of stain/sealer once the deck is installed, otherwise the lifespan of the deck can be impacted