Be careful. Single 24x60" sheets of 3/4" MDF are pretty easy to lift. A doubled sheet is manageable. The countertop - 24x72" panel of 1-1/2" oak - weighs something over 100 pounds. It takes real care to lift safely. The joined top - 3" thick of oak and MDF - is past the range that can be lifted safely by one person. Don't try. Get a friend to help, or rig a block-and-tackle.
While a strict figure for the bench’s weight capacity is not available, a quick browse through their other stand and bench products shows a general weight capacity well above most other brands. As such, while we cannot say for certain that this bench provides the best weight capacity, it is more than likely that it the capacity is similar to the other products in the catalog.