Lately it seems like there's two tiers with the first being guy who watched a video on youtube and the second being true expert but with a huge chasm of price differential and next to nothing in between.
one of the best things about slab living is no need for heavy underlayment. a simple sheet of waterproof paper or plastic suffices thereby minimizing any flex in your flooring of choice.
yeah environmental factor play a more accurate part to slab care than a pier/beam setup. if you live in a waterbed zone with lots of clay and lots of rain, a slab can be a headache to maintain