There’s never a single metric that you can use to decide “better” - it depends on the needs of the project.
I agree that there is no single metric to decide "better". But in most cases properly calculated LCOE, the cost of a kWh over the lifetime of the solar panel system is the single metric that matters. Because why pay more for electricity?
Only in special projects, like solar panels in space, cost is not the most important metric.
For example utility scale solar can be less than 30% the cost of a residential solar installation, but also adds profit margins, interest rates and distribution costs to a residential customer.
In the later Ringworld books Larry Niven introduced solar 'panels' sprayed onto any surface and wirelessly broadcasting power. The DIY installation costs would now be almost zero.