We love these countertops too! Concrete is very durable...it has to be sealed which protects it from stains and water damage.

were these manufactured off site or poured in place

White quartz is much more chip-resistant and stain-resistant than concrete, with a very similar to look to what is shown here. See "Concrete" series by Caesarstone. Slab thickness is only 3CM but can be built up to any desired dimension. Concrete is very porous and has to be sealed and regularly resealed for protection from stains.

Elsatohouse, these tops were manufactured off site. They are approximately 10 years old at this point. I agree with Lane 100%. Concrete tops require love and care to avoid a weathered patina. The popularity of the concrete look has inspired many quartz manufacturers to replicate it. Ceasarstone has the best look to date. If you are looking for a smaller area, take a look @ Marbelite Compazzo

They are great for bathrooms.