Linux is the
operating system I use. It's better than
Windows in about every respect which has even the slightest relevance to me. I do, however, still keep
Winblows around to play games on and for when I have to run
Windows-specific software or browse
Windows-specific web pages and don't have a choice, such as was the case very recently when I was applying to
medical school.
Linux's major problems:
GNOME and KDE are both out there, but neither has gotten session management right.KDE develops slowly. GNOME would be good if they could ever get session management right. I just use GNOME for the panel.
Some software uses memory like there's no tomorrow. XFree86 is a good example. Mozilla, which is the only full-featured web browser which has been updated in the last few years, is unstable and has memory leaks all over it, which the developers claim don't exist, and which eventually cause Mozilla to use gobs of memory. This will eventually be fixed. Windows, surprisingly enough, sometimes (but not always) does a better job at this. (Of course, Windows software is often more broken, and rarely has source available.)
Richard M. Stallman (RMS) sticks his nose in and makes everything a political issue. Sometimes he has good reason, but other times he doesn't (e.g. the GNU/LINUX/lignux crap). Other zealots tend to do similar things. The OS is hopelessly GPL-infected.
Total lack of encrypted filesystems and encrypted swap in later kernel versions. This is changing, though.
Linux's major strengths:
Security. It's infinitely more secure than Windows. See, Windows has absolutely no security to speak of, so we can say that it has zero security. Any security makes something infinitely more secure than Windows. It's mathematics. But anyway, Linux does tend to do security really well. For various reasons, mostly organizational rather than technical, it doesn't do it as well as, say, OpenBSD.
Functionality. Unless you're playing high performance computer games or something else which requires some kind of driver support which isn't available for Linux (and that's usually because the manufactuers never bothered to write a portable driver or release specifications), or you're in a position where you need to buy and use a lot of off-the-shelf software, Linux tends to be more functional. This depends on what you're doing, and whether you know how to do it, of course, so your milage may vary.
Most software for it is open-source. This means that I can fix bugs and change things myself. This is a major plus, unless you don't know programming or don't care.
Development utilities are freely available.
It has functional telnet and ftp clients, which is more than I can say for Windows. Windows hasn't had a functional telnet or ftp client ever, and they've had over five years to get it right.
Choice of operating system all depends on what you're doing. However, I will close by saying that Microsoft's total and blatent disregard for even the most rudementary security is a big mark against Windows. Linux (and BSD, and most other Unices) at least get that right. It depends on what is important to you. (I tend to find it important not to get hit by lame exploits like the ILOVEYOU visual basic worm, myself.) Your milage may vary.