I love BeOS and had NeXTSTEP 3.3 (& later OpenStep) and BeOS running in my office. There was no real comparison, NeXTSTEP was better in every way except doing video demos. It was easier to program and had a decent UNIX. NeXTSTEP was multi-user. BeOS was superior to quite a lot of the other OSes at the time though.
We will really never know, but I suspect there were some serious problems when Palm bought the code and couldn't build a phone / PDA OS out of it.
Imagine if our iPhones ran BeOS.