Below you will see a quick comparison between Cedar wood and Pressure Treated Pine wood. 
Cedar is not always readily available and thus the price may be higher at certain times in the year. Cedar will often cost 1.5 to 2 times as much as pressure treated wood. Pressure treated pine wood is readily available and often not expensive.
Cedar gives your fence project a much more natural look than pressure treated pine. Natural Cedar is a soft wood that comes with very little imperfections and there is no warping, cracking, or shrinking, and hold up very well to the elements. Pressure treated lumber often is speckled with knots and other imperfections and sometimes can begin to twist and warp soon after leaving the wood mill.
Cedar unlike pressure treated lumber is not chemically treated to fight off wear and tear from the weather. Cedar has many natural properties that help it fight off the weather elements, however it is highly recommended to seal the Cedar with a clear seal to retain the wonderful natural deep red color.
At Capitol Fence we take securing our fence posts properly very seriously. 
Capitol Fence uses ACQ (alkaline copper quaternary) pressure treated southern yellow pine. ACQ is an environmentally safe formula that is arsenic free and provides long term protection from dry rot, decay and insect damage. ACQ-treated wood is safe for use in the garden, for picnic tables, and in areas used by animals, fish, and children.
Pressure-treatments will vary depending on intended use: Ground contact wood is more heavily treated to resist water damage from wet soil. Properly used, pressure-treated wood will stay strong and useful for decades.
Pressure treated wood can be painted or stained to match any existing deck or patio. Even if you don’t want to change the color of your wood, you should apply a clear water repellant sealant to protect it.
Wait 0 to 90 days after installation to allow the wood to dry before applying stain/sealant or paint. During the treatment process, wood is injected with ACQ and becomes damp due to chemical treatment. Capitol Fence recommends using a high quality latex-based paint or a linseed oil-based stain. Stain may be transparent or semi-solid. Stain may be added to sealant, or you can use a sealant that is premixed with color. Painted wood does not require additional sealant.
When applying paint or stain to pressure treated wood, make sure the boards are completely dry. Try to apply on a dry but overcast day with the temperature above the limit specified by the manufacturer.
Brushing provides the best coverage. Be sure to brush all exposed wood and work the sealant into the end grain. If you spray, follow sprayer instructions especially regarding distance from wand to wood. Holding the wand too far away can result in inadequate coverage. Even when spraying, it is a good idea to use a brush on the cut ends and around joints.
Follow the manufacturer’s recommendations on weather conditions when applying. Sealant cannot penetrate the wood properly when temperatures are too low.
Caring for your fence can be quite simple once you understand what can cause damage to wood and why. High quality pressure-treatment makes wood impervious to damage from insects (termites, carpenter bees, etc.), bacteria and fungi (the cause of dry rot and decay). As long as your wood has been treated properly for the location in which it is being used, you shouldn’t have to worry about those common causes of fence failure. But pressure treating doesn’t provide long term protection from the effects of weather.
UV light from the sun weakens wood by breaking down its fibers, and exposure to air draws the natural protective oils from the wood leaving it vulnerable to cracking as it dries. To protect your wood from the effects of weathering, apply a good quality, linseed oil-based stain/sealant once each year.
Pressure-treated wood used for fence posts and footings will be treated to a higher level of resistance (called “ground contact”) than wood used above ground. For the above ground portion of your fence, debris such as leaves, mulch, and trash can block moisture from evaporating and create long term wet areas that will be vulnerable to rot, decay and termites. Keep your fence clear of leaves and debris and make sure that mulch is not piled up along the bottom boards. As long as the wood is exposed to freely moving air, the pressure treatment will be effective.
To sustain the life of your pressure-treated fence, proper hardware is a must. At Capitol Fence, all nails, fasteners and fittings are hot dipped and galvanized to protect against corrosion. When non-galvanized nails and fasteners come in contact with pressure-treated wood, they corrode and rust.