A foreword: My work is in the IT department maintaining some MS driven servers, organizing our external business contacts that are data related, defining and sometimes coding data interfaces, coding some internal tools and so on. Our whole SW architecture is basically MS or Oracle. The excepts are the hosts of our virtualized servers which are Linux systems. Personally I grew up (I'm 45 yo now) with Commodore PET at school and TRS-80 in the early years of my studying and later with MS-DOS, DR-DOS and Windows 3.0 and later. I had some deeper looks into OS/2 (which was one of the greatest OS ever built in my believe, lightyears ahead of Windows at that time) and Linux since kernel < 1.0.
I think a common misunderstanding is that Linux wants to be a "better Windows" (or at least an equal). And that Linux have become more similar to Windows (and works on that point).
Basically Linux is very different. It has a monolithic kernel which means it lacks some flexibility regarding changing hardware but provides some performance and stability benefits. In terms of security Linux is still far ahead of Windows but the latter has worked up to some point using third party SW and using stricter permissions than in former times (at least with the business and enterprise versions). Indeed I haven't had no problems with viruses whatsoever the last few years using free anti virus sw. But my last system at home running XP suffered badly from limp permissions and chaotic sw installations of my two sweethearts ... now with W7 thing are getting better (with Linux there wouldn't have been no such hassles from the outset). MS seems to learn from Linux. At this point It's surely not the other way round.
Software installation isn't worrysome with Linux -- it may have been, but since you can use repositories it's far more easy than with Windows. Just make some ticks to the sw you like to install and give it a go. No crawling the net and surfing to vendor sites here and there. If you use Linux as a desktop system with average requirements it's perfect to you. It's "windows thinking" what makes you a hard day.
On the other hand, if you need very special sw or you have to install newer sw versions (or newer versions of device drivers) than that found in the repos things may become more difficult than you are used to (from windows). In this case you have to dive far more deeply into Linux knowledge to achive your goal. On the contrary the ease of changing device drivers within Windows and the not obvious risks performing those system changes leads far more easily to an unstable Windows system.
GUIs tend to become more similar due to the needs of usability. Of course here and there is some mimikry. Developers use to look how others solve a problem and usually they use APIs and libraries (that are often cross platform compatible) despite inventing the wheel once more. But basically the GUI is quite different from Windows'. IMO one of the worst misconceptions of MS Windows is the Explorer as beeing a unity of the file browser AND the GUI shell. This misconception means a ridiculous dependency from Network and file I/O operations leading to far more stuck GUI sessions, often bad responsiveness and general unstable situations. I this respect Linux sports a far more module based approach. Having several independent subsystems provides at times some compatibility problems but generally a significantly stable system.
I could go on and on ... In the end it all comes down to tastes and needs. If you don't like Linux and prefer Windows the Linux world just don't bother (ok, there are enterprises who bother ... but that's an other story). I use both. And many others do as well. Do whatever you like (as long it's legal) but don't bore us ...