Looks bad, but I wonder whether he got a faulty unit or if it is a widespread problem. It would be odd that Apple and review sites wouldn't pick up on it if it decreases performance to such an extent.

"Review" sites nowadays heavily rely on joke of a benchmark suite called "Geekbench" which only measure burst performance only lasting seconds.

More serious sites like Anandtech only focus on performance of the chip itself (not the product it's in) , so they apply extra cooling measures to eliminate that variable from the equation.

So no, you can't actually rely on mainstream reviews and benchmarks to decide on a specific laptop.