I don't use a media player often, but I've been watching videos from family lately. Are there any clear difference or reasons why I should use WMP over others such as Real Player?

It tends to be the only one that plays the majority of video formats. Others play one or two, but not all. It's about my favourite of all windows programs.

It's really about how widely used the program is, just as with any default Windows program. Because so many people use it, you can be sure that any videos that play in it will play on another Windows computer, which makes sharing videos easy. That is at least one advantate that I can think of, anyway.

I find that WMP is easier for video and music than real player because my real player won't always play every format, so I end up switching back to WMP anyway.

I find that WMP is alot better to watching movies as it has all the codecs I need, if not, it's easy to find the right ones for WMP on the internet.
WinAmp is better for music too, I think.

I think with many people it's just because it comes up by default whenever you try to play a video - or at least mine does. It does the job that I need it to so I've never thought to bother trying anything else.

I use it more often than anything else. It works well and hasn't given me any real issues. The features are simple and easy and I like it that way.

I use WMP and VLC player. I prefer VLC player because it more simple and user fiendly.