The best repair method is the one that takes into account the needs of the structure and the objectives of the homeowner.
If your concrete slab house was built in the past 15 years, most often straight steel piers are the best. They are driven to load bearing strata, and I don’t just mean compacted clay.
With older concrete slab foundations, houses are usually best repaired using straight steel or helical steel piers. Helical steel piers are the preferred method if the concrete is not strong enough to stand up to the driving force required of straight steel.
By comparison, concrete cylinders require 4 times the driving force of steel due to the difference in diameters. Steel has an end surface area of 6 square inches, while concrete has an end surface area of 28 square inches. This comes from the equation for end surface area of a cylinder: A=πr2
In general, pressed concrete piers are inherently cheaper than steel piers due to the material cost of steel. Poured concrete are a little cheaper, but quite destructive to landscaping and with no assurance that they are on load bearing soil or strata.
At leased one foundation repair company markets a hybrid steel and concrete pier priced as if it were the premier foundation repair method in Dallas and Fort Worth. With good marketing and a million dollar spokesperson, it sells.
As a general rule, steel piers drive consistently to hard load bearing strata. Concrete cylinders, and concrete cylinder pilings mixed with steel will drive to compacted clay. The cylinders exert too much frictional force to drive as deep as pure steel.
For more info, see a comparison of steel and concrete at Granite Foundation Repair.com