Welcome to TFP! I'm down south and right in the middle of the Texas black clay soil belt. It's horrible. The soil gets dry and crumbles in the summer, then swells in the winter months with lots of rain. That's one reason we went with fiberglass, just in case a little movement might happen. In all honesty though, is it really better than a well-built gunite? I doubt it. The key in either scenario is how well the area is prepared, the pool constructed, and backfilled. Obviously we have thousands of each type of pool in our areas and they do fine. There are some pros & cons of each pool type which are discussed on this forum quite a bit, so I'd just consider all the options of either pool type and not just the soil to help you determine which type of pool is best for you and your family.