Did not really form an opinion about brightness, but the fact that I don’t recall suggests that they were not noticeably bright. But take this response with a grain of salt.
As to soundstage depth, size, my anniversaries bested the P3s in my home,in my opinion, with my electronics. However, the harbeth dealer suggested that since I listened to the P3s positioned optimally for the anniversaries, I should have tweaked their position for the harbeths, and I might have had a different opinion. Time limits prevented that. So again, a grain of salt..
But I never compared the 10s to the P3s.