It's true that some seats will probably outperform others, but we have no way to know which seats. We don't know if steel bars or headwings or head pillows or "true side impact protection" or whatever the newest marketing thing is are a significant advantage or not.
We do know that RF for the maximum possible time is a major safety advantage, and Britax seats do not allow that for many children, so in that way, if you RF to the limit and have kids who are taller rather than heavier, the Britax may be less safe than a seat with a taller shell.
I am aware that this is splitting hairs to some extent, though. They are certainly safe seats within their limitations. And they're not terribly limited either. But there are better options out there. Of course the Radian (one of those better options) also has steel bars....if only it didn't have install issues, lol.
There's no perfect seat! My current favorite is the Complete Air, which has no steel bars and kinda gimicky head pillows, but it RF to 40lbs and has a very tall shell and installs upright for older kids with good legroom. My DD is tall and hates being reclined, so that obviously influences my opinions.