Current solar cells are only cost-effective in limited scenarios, it's nice that these could go in more places but even if they reach cost parity with what we have today, the would be less power. We're going to need to see huge reductions in production cost or energy capture before this becomes viable.
Good solar panels for homes and solar farms are 15 to 22% efficient.
In many ways efficiency is irrelevant. If a panel were only 5% efficient but that produced 200% of a families power requirements in a normal install and broke even after 1 year that would be awesome. On the other hand if a panel were 95% efficient and returned 5% of families power requirements and broke even in several decades that would be terrible.
It seems a rating that shows how long it takes a panel under [a properly defined] "average" solar illumination to pay for it's own construction (both in money and power) would perhaps be useful and not too difficult to test and verify.