When I explain to Windows users why GNU/Linux is better, I always try to
focus on the following points:
1. You get no viruses with GNU/Linux, it has a better concept of security and
less viruses written for it
2. You can install software for any purpose easily from the software-center.
No need to activate software with keys or pay hundreds of euros just to get a
legal copy for PERSONAL use.
3. The system is much more stable than Windows, it never slows down over
time.
The moral issues may be more important for the people who are aware of them,
but if you never thought about software choice as having something to do with
morals, it's very hard to understand the concept. So I try to talk about all
of the technical advantages first and later tell them what GNU/Linux is
really all about.