I have a large deck with cedar deck boards and it's beautiful when it's clean, but, if I had to do it over again I would not build a deck using wooden decking of anytype. Way to much maintenance to keep it looking good. If you're considering cedar then check out the composite decking. It's about the same price and zero maintenance. With both cedar and pressure treated (PT) you need to seal with a semi-transparent stain yearly on the horizonatal boards and every 2-3 years on the vertical boards. That includes cleaning prior to sealing and then the time and expense of applying a good sealer.
Cedar is softer than PT but a bit more stable in that it doesn't twist and crack quite as much. Using either boards you need to use a triple galvanized screw or stainless steel screws, otherwise the chemicals in the new pt will corrode the fasteners and rust them in two withing a few years.