There are pros and cons to both poured concrete walls and block walls. Poured concrete is a solid mass, so it's more resistant to moisture and pests. It's also less likely to suffer from settling or cracking than block walls. However, poured concrete is more expensive than block, and it can be difficult to repair if it cracks or becomes damaged.

There is no definitive answer to this question as it depends on a variety of factors including climate, project budget, and personal preference. With that said, poured concrete walls are often seen as being preferable to block walls since they are less likely to leak or experience water damage. They are also generally considered to be more aesthetically pleasing. However, poured concrete walls are typically more expensive than block walls, so that needs to be taken into consideration as well.