What is the big deal about Linux?

I am a soon to be college student who just received an HP laptop with Windows 7. For my entire life, I have been raised on the windows operating systems (XP) and I am used to it. Recently, I heard about the Linux operating systems, and have been intrigued by them, so I have tried to research as much as I can about them. I am not too computer savvy, but I feel as if I know at least the basics for running Windows. I have heard that Linux is extremely hard to work and can be very frustrating. I have also been told that I will hate it because of its complexity. What I am asking is, what makes it different than Windows? and I don't want answers that will tell me how much faster or better it is than Mac or Windows, because that's all that I was able to find on the internet. What I would like to know is how it actually works. I know how Windows works: You turn it on, it brings you to the log-in. You sign into the computer with your name and password, and it brings you to your desktop. Then you just activate the programs. Its quite simple, and it makes me wonder, how much harder could Linux be? Could someone please explain to me what makes Linux so much more of a tough operating system than Windows or Mac? Why would it be frustrating at times? What do you have to do to actually run the system? Any feedback would be great. I am also thinking of dual booting Windows 7 and one of the Linux Operating systems, probably either Linuxmint Felicia, LXDE, or 10 KDE. Which, as a fairly novice computer person, would you suggest I use? Thanks