I started out using KDE while I was leaving Windows behind. I now hate the KDE "experience", but I constantly have to help my Dad with it. I am constantly bugged by desperate Windows users looking for help but unable to make that dreadful jump into a free and secure operating system like OpenBSD, even when I offer them a USB drive to check it out.
What exactly are you looking for when you say a "GUI"? That really covers a huge field. What does it need to cover? I use spectrwm. Fits me perfectly. Fast and low memory. But it might not be right for you. Try a bunch of different window managers. There are a lot of crappy ones. A few good ones. Chris Bennett
