Microcement and polished concrete can look similar, but they are built differently. Microcement is a thin finish applied over a suitable base. Polished concrete is the concrete slab or topping itself, ground and polished to create the final surface.
Choose based on the construction, not only the appearance. Microcement is often used as an applied finish or renovation overlay. Polished concrete makes sense when the concrete slab itself can be designed and finished as the final floor.
A similar look can hide a different construction. A grey seamless floor in a photograph could be either material, but the construction and work schedule are different. Polished concrete starts with placing and curing concrete. Microcement starts with checking and preparing the existing base. This affects weight, thickness, thresholds, joints, work order and the trades involved. Choose the construction method first, then develop the visual finish.
When polished concrete may be better. Polished concrete can be a good choice when a new slab or topping can be designed as the final floor. The exposed aggregate and natural changes in the concrete become part of the look. The project must also allow for concrete joints, curing conditions and greater depth. Changes become harder after the slab or topping has been placed.
When microcement may be better. Microcement can be useful when the project needs a thin finish, controlled colour, matching walls and floors or a renovation overlay. The same finish style can continue across several surfaces. It still depends on the base and the protective system. A thin finish still needs proper preparation, moisture checks and joint planning.