Every O/S has its limitations, even Ubuntu. Things I like about Windows 8 Preview Release over Ubuntu or even Windows 7 include super faster startup time, excellent hardware detection, excellent multi-monitor functions and options, improved file copy abilities, greatly improved task manager, improved antivirus integration, improved taskbar abilities. I do miss the start button rather than the start screen, but just takes some getting used to. The Windows store is also useful.
I replaced Windows XP on an old pentium dual core pc with 2gb of ram and its a night and day difference. Windows 7 would never have run as smooth on this machine. A step in the right direction.
I also appreciate Linux and Mac O/S's as well and will almost always be more secure, as they are less targeted by virus writers because they are not as commonly used.
Oh yes, and the screen font smoothing wizard is incredible and runs for each monitor individually improving the clarity of each monitor far beyond what any other O/S I've seen can do.