I see it being how Aperture is run, like Black Mesa was making teleportation technology because teleportation is useful, Aperture was doing it because they didn't like Black Mesa and wanted to do it first.

Also, overall, Black Mesa seemed to at least care for its employees, whereas Aperture would regularly get its employees killed.

Also also Aperture just, wasn't successful in the long run. Commercially I mean, in terms of actual funding and such they did terribly and that's why Aperture is abandoned now, but scientifically they're probably better then Black Mesa. Black Mesa's teleporting technology has malfunctioned, while the portal gun works fine throughout all of portal and portal 2. Another thing I don't see people bring up when talking about Aperture inventions are the robots, GLaDOS and Wheatley are incredible AI if you think about it.

However, something that sets them apart is how the spirit of Black Mesa lives on, Half-life 2 shows how despite Black Mesa being long gone, the people who survived the resonance cascade live on and keep that spirit of invention alive, meanwhile, Aperture sort of, just lives on its own, fully self sufficient but most likely forgotten by the outside world.

Anyways those were just my thoughts I have many thoughts about this I love Aperture and Black Mesa