Haiku currently only works on x86 systems. Minimum memory required is 128MB. If compiling Haiku within itself, 1GB of memory is recommended. Haiku has been tested to work on CPU's as slow as a Pentium II 400MHz, and requires as little as 600MB of drive space.
There are over 1000 open tickets on Haiku's bug tracker and over 3000 closed items. If you find what you believe to be an issue please search our trac to see if it has already been reported and if not file a new ticket: http://dev.haiku-os.org/