That leads to the pros and the cons.
According to an article entitled "Using Composite to Build Your Deck - Pros and Cons" on the Associated Content website:
The major myth right now is that Composite means "no maintenance"; this is stereotypical and untrue. Although it can mean lower maintenance, anything that you want to stay in good shape over many years needs standard cleaning and care. So the question is, if you still have to care for composite, why choose it? The following is a list of reasons:
1. No annual painting projects. Composites come in many different shades and they are already coated so you do not have to spend the time staining your deck.
2. Less issues with rotting and termites. Due to the plastic that is coupled in with the wood fibers, you do not have to be as concerned with termites or eventual rot.
3. You can usually obtain a warranty on composite where with lumber you cannot. This product, being man-made, has more backing its production.
4. Many composites have a hidden fastener system so there are no screws or nails to get snagged on. Also, the surface is pristine.
5. Composites have a great and long-lasting durability, no splintering or excessive scratching.
However, composites are not perfect, and there are a few things you need to keep in mind before spending the money on such an expensive product.
1. Most composites come with application instructions, and you need to follow them to the letter, so that your warranty is valid.
2. Composites seem to attract biological growth, so you have to make sure you clean them every few months.
3. If you do decide to paint your composite products, you will have to do so annually because eventually, due to the plastic within the boards, it does not adhere as well.
4. Composite is not structural, so you have to make sure you use treated lumber for all your structural pieces.
Concrete lasts a long time, needs little maintenance, can be fun with sidewalk chalk for the boy...but it can be slippery in winter, hard when it comes to falls, it can crack, and it can get hot (but I suppose, composite would get hot, too).
I think, ultimately composite will LOOK better, plus it is cheaper, but concrete might last longer and be more functional.
Neither will require much maintenance, and neither will be hazarded by bugs (we have to contend with the icky carpenter ant here in the Pacific Northwest). Neither will rot (which is always a worry in wet climates like ours).
It does appear that moss and mold will collect on the composite (I'm not sure about concrete). And though concrete can stain, I think the composite is more likely to hold marks.
It might be easier to replace small sections as needed with composite...but it will be just as easy to add on to both. Concrete will be a better (in fact, necessary) base if we choose to put in a hot tub at some point.
So, yah...I'm still divided. I think I'm leaning more toward the composite, mostly because it will be about $400 cheaper and because I truly think it will look better. I know that now concrete can be dyed and blended in ways that make it look completely amazing, but that isn't the cost I'm looking for. The basic gray, brushed concrete is what we were quoted in the estimate. So, for the money, the composite will probably look better (since we can get a color to match the trim of our house).
I think D. disagrees. I think he is leaning more toward the concrete.
Hmmm...wife vs. husband. Don't know who's gonna win yet.