I am still in the midst of retirement planning. Now the option of new home construction is on the table again. I am waiting to hear which option my builder will recommend for the foundation; concrete slab or alternatively piers of some-sort. If the contractor can make me feel comfortable with a concrete slab, I will go with that as a less costly option for the ranch home I plan to build. However, I don’t want to be foolish trying to save money in the short run, if a more expensive pier option is the better choice. Because it’s new and modern construction, I do not expect that I would be tearing up the concrete for a later upgrade in plumbing or utilities. Also, I don’t think I would need a crawl space in the new house. So that’s a plus for the concrete slab option. And I would be building in a warm weather state; expansive clay soil is very prevalent there, I am told. Any suggestions?
Just make sure there are no large trees next to the slab. We have seen a house where a giant Douglas fir’s roots lifted a corner of the slab our of the ground (possibly cracking it - but it was hard to see under the carpeting).
How expansive is the soil? What’s the soils report indicate? Typically, a soils engineer would make the recommendation.
You should have a recommendation from an engineer, in addition to the builder. A builder generally isn’t going to want to deal with piers. An engineer will, in general, be MUCH more conservative. If they do piers, then you need a soils report to see how far down and what the criteria are for determining depth (compaction, bedrock, etc.). Piers may be billed by the foot of depth. All this gets complicated, but you don’t want the house to settle and have problems. If you have questions about what they are recommending, post them here in detail, as there are some structural engineers on the forum (MaineLonghorn for one).
We have a “settling” rental property, and have spent upwards of $100K trying to get it stabilized and repair all the damage.
SO NOT my area of expertise.
But as someone whose friends lost homes to Superstorm Sandy, I’ve got to ask: Are you anywhere near a potential flood zone?
Lots of homes here on Long Island are "Levits’-- built on a concrete slab just after WWII. But we’re central LI-- a good 20 minutes from the ocean and any potential storm surge. (Basically, we’re the part of LI that people evacuate to in a storm.)
As a structural engineer, I would second @sylvan8798’s advice and retain an engineer to advise you on the matter. There are a lot of variables to consider. If the engineer is familiar with the area, he or she MIGHT not need a detailed geotechnical (soils) report - we usually don’t request one for residences.
If there’s clay, the engineer might want you to use piers. Clay sucks. 
Also, be careful if there WAS a big tree where the house is built. In our neighborhood, two of the lots were dominated by huge trees. The roots went down very deep and there may be some settling as the deep roots rot long after the foundation was poured and the tree was removed.
Agree with everybody else to consult an engineer. I’d just add that you should be sure your builder has experience with whatever you end up choosing; if not then pay extra to have the engineer or architect oversee and approve that stage of construction. Regarding post-tension slabs in particular, I’ve read that the majority are not tensioned correctly.
For the cement itself, you also want to make sure that someone knowledgeable inspects it prior and during the pour to be sure it’s good, as I’ve also read that issues can arise there (e.g. cement mix not correct, too old, etc).
I’m not an engineer, but having seen homes built in areas (specifIcally the area where I live) with expansive clay soils, I’d personally be more comfortable with at least engaging the services of a geotechnical expert (maybe just a meeting) and potentially, if necessary, perform and analyze test borings of the site.
Not knowing the area of your future home, some areas can have high water tables and/or rock ledges too, which could also change the design and/or location of the foundation. And I’d feel far more comfortable having the geotechnical engineer inspecting the concrete pour as well, which @anomander mentions above.
I’m not really sure what you mean by piers. Continuous foundation with a vented crawlspace? Continuous crawlspace built like a conditioned basement?
But the short answer is it depends on where you live. No one should be talking only to the builders about what they think. They have no training and often think that because this is the way they’ve always done something it’s okay. I’m required to take 36 hours of continuing education and I’ve learned that a lot of what was okay back when I was in school no longer is. Building codes get updated and we know a lot more about how insulation works. A house is a huge investment talk to local architects and engineers. You’ll get a better designed and safer house.
Around here we usually build basements, but because we often encounter ledge I’ve had to pour slabs that get pinned to rock instead.
https://buildingscience.com/documents/insights/bsi-015-top-ten-dumb-things-to-do-in-the-south
https://buildingscience.com/documents/information-sheets/crawlspace-insulation