Some people have done A/B test on that vs. their old layout. I'm sure it worked great for a lot of people - again, vs. their old layout. That doesn't mean it's

Some people have done A/B test on that vs. their old layout. I'm sure it worked great for a lot of people - again, vs. their old layout. That doesn't mean it's the best layout. There's no such thing. It's now being copied by sites that should probably not use it. The key is always to test, never assume, and never assume you get to the final answer. Constant optimization is key.