Never had a BeOS system before, but I have been trying Haiku OS in dual boot on my 14" AMD laptop. It worked well so far, the only real problem with Haiku is the lack of a serious brower. Falkon is the one more feature complete, but crashses continously. WebPositive is more reliable but is slow and lacks many modern features. I tried also compiling Otter Browser myself, but as it uses the same engine of Falkon it crashes as frequently.