SR-71 was severely G-limited and subject to unrecoverable pitch-up beyond relatively low angle-of-attack maneuvers. Perhaps a more recent design allows more athletic flying abilities combined with the raw speed.
I am aware of those problems with the SR71, this why I think this is likely a sophisticated drone rather then a manned aircraft. I have had more then one aerospace designer comment to me that we may be passed the age of advanced manned aircraft.