Start with the slab.
Is there an old coating to remove? Are there cracks, oil contamination, or moisture concerns? Product instructions define the substrate requirements. The work needed to meet those requirements can be a significant part of the project.
Compare a complete specification.
Record the products, layer sequence, coverage, and finish details in each option. Do not assume every professional installation uses the same system, or every store kit has the same limitations.
Value your time and the rework risk.
Consider equipment access, preparation, working time, application conditions, and how you would handle a problem. Ask a contractor to explain these responsibilities in the proposal so you can make a fair comparison.