It's a nice thread, and cdoerfler is either bonkers or just a sales person; in many cases it may be hard to tell the difference. My only issue with the thread is that other bits of mis-information is also being included by other users. The two most egregious one's I've spotted are “Backfeeding breakers is also iffy, only certain types allow it” and “For a proper surge protection the blue box would need to be inline, not detached.”
For the first I’ve never seen a breaker that isn’t bi-directional. Some of the more ‘intelligent’ trip units can have reverse power flow detection and such which may trip a breaker if the current flows opposite to that which is expected, but that’s about it.
For the second the vast, vast, vast majority of surge suppression is carried out by a device, whether it be a MOV, SASD, TVSS etc, that is placed in parallel with the incoming line. The feed to the protection device needs to be as short as possible but the device is certainly not put in-line.
My 2 cents worth