Decking comes in two main forms which is pressure treated wood and composite decking, both types last a long time if they are properly looked after.
The main and most obvious difference is the cost, composite is around 4 times the cost of wooden decking as the boards are much more expensive and the supports are metal. Both can be slippery in the wet.
Possibly the best point about composite decking is the fact you don't have to paint it every year. That said if you have balustrade around the decking, that is normally wooden and will need painted every year. If you have loads of cash go composite and put in glass balustrade then it is a wash a couple of times a year.