I was trying out Haiku, a updated and maintained version of BeOS. The interface is a neat but takes getting used to as it very much different than windows or any flavor of linux. The icons are cute and performance seems well even though I was running it in a virtual environment. It uses a unix like command shell, so it pretty easy to use the command line if you need to use it. It does come with a web browser called Net Positive, which seems to be a fork of Safari. However, it is a old version and does not support HTML5, flash is also non existent. I believe somewhere someone might have ported gnash to it for flash support but I do not have the time to hunt down what people have done to support modern technology and media. I found a port of a mozilla based browser but it was based on version 2, there is another but requires installation of QT, thus killing this as a novel experiment of a alternate OS I may experiment on a netbook as it is so greatly inferior to most modern operating systems (and I am not about to go and compiler firefox 4 for it).
It would make a great alternative OS for experimentation but its usability factors prevent it from being a good alternative if you want a light weight alternative to current operating systems. The file navigation system needs to be improved as well. A more robust file manager would help rather than a bunch of small windows each time you navigate to a particular folder on the system.
If this OS is not modernized to support out of box, current technology (HTML5), etc. Then BeOS is really dead. And the project that spawned this is doing not as a alternative OS but just a hobbyist toy. After experiencing it, I would keep it in a virtual environment. It lacks too much to be installed as a live system. I cannot recommend it.