I use it since version 8.10 and do not miss Microsoft Windows.
Especially because I use my OS to browse the web. If I want play games I use Windows wich is still on my HDD.
If you want to start Windows software there is WINE which can run most Windows .exe software.
Ubuntu also exists as Kubuntu, Xubuntu, Lubuntu which use other desktop enviroments. Last ones need less RAM and CPU and can run on older Computers too.

Ubuntu has a very great community and you will find help in a range of Ubuntu forums.