The bench I will be describing differs from both of these in a couple of areas, the most significant of which is the top. Allen's top was made from three layers of 3/4" medium density fiberboard (MDF), topped and edged with 1/4" hardboard. Christiana's top was just two layers of 3/4" MDF. My top is two layers of 3/4" MDF edged with 1/2" oak and topped by a 1-1/2" thick edge-glued oak Ikea countertop. My top is more expensive in both time and money than either Christiana's or Allen's. If you're looking to build something fast and cheap, I'd recommend Allen's approach over Christiana's. The hardboard significantly increases the durability of the top.
Workbenches have flat tops, though sometimes at the rear there is a cavity called a tool well that contains tools and components (and prevents them from falling off). One advantage of having the well set into the top of the bench is that, even with a variety of objects in the well, a large sheet of material can still be laid flat over the entire surface of the bench; the contents of the tool well offer no interference.
Grizzly is a company currently undergoing an upheaval. This brand was once known as a manufacturer of professional grade tools and equipment for woodworking products. Though, in recent years, that reputation has begun to slip a bit since being bought by the Chinese company SIEG. These days, whether the Grizzly product stands up to its previous standards of excellence often has more to do with what you are buying than the company itself.