That was actually a fairly awesome OS (for its day). Many folks thought Apple would buy it. When they purchased NeXT, instead, a lot of us were disappointed.
However, all these years later, I'm very glad that BeOS wasn't selected.
Mostly because of the UNIX subsystem. Having all that horsepower under the hood has been awesome.
Also, NeXTStep became Cocoa, which knocked PowerPlant into a cocked hat. That may not be as compelling an argument. I heard that the BeOS framework was damn nice (never tried it, myself).
Besides that, it is also very likely that Apple would have remained stagnant (or worse) if Steve Jobs had not been brought into the fold. I am not into persona worshipping, but Jobs brought some well-needed focus to a sea of overpriced beige boxes.
However, all these years later, I'm very glad that BeOS wasn't selected.