I've used a couple systems for multiple desktops on windows. I always found them to be a bit slow and buggy. I haven't used the sysinternals one though. It mentions that the others fake multiple desktops by slectively hiding applications, so that may be why they were buggy.
I too have ubuntu linux on my laptop. Have installed it for development purpose. I really enjoy using it. But there are practical issues like any software you want to install ubuntu is not the favorable os.
I used Ubuntu a few years ago on an old work laptop for development of an ARM Small Board Computer programming. It was not too hard to start using Ubuntu but the setup was a little difficult for the development tools (took a little bit of work). I liked the speed the old laptop demonstrated and while familar with non-graphical interfaces (worked on SUN workstations years ago) I did like the graphical windows on Ubuntu. On the whole it worked well and the tools (needed to be on a linux machine) once setup ran fine.
We have a fleet of laptops, and an old desktop, that became uselessly slow with the pile of "fixes" from M-soft that accumulate over the years. They have been reborn into fast and reliable Ubuntu machines. Even my wife will login to the Ubuntu server to do web/email tasks a few times per week when the (one and only) Win7 system we have goes thru it's bouts of sluggishness. I've done a number of "right-the-first-time-with-no-blue-wires" PCB designs with gEDA software running under Ubuntu. Ubuntu runs all of the common tools I use for my day-job as an EE at <major_semiconductor_manufacturer> , and does not have the security/reliability problems so prevalent in Win machines. I've also done plenty of FPGA development on Ubuntu as well. System-administration is fairly simple, and I entrust our son & daughter to maintain their own systems even though they are not sci/tech majors in college.
The future of Win8 in our house is rosy, however, because we will be purchasing a new system with Win8 (mainly because Netflix wont stream to Ubuntu, yet....), and I get to waterful the almost-useless Win7 machine over to Ubuntu, where it will replace the 10-year-old Ubuntu server.