I have used unix for 14 years now. I really do like it. It may not have all the 'bells & whistles' of Microsoft, but its stable, VERY stable.
Microsoft made a few 'assumptions' which ticked me off royally.
#1 is 'assuming' I am too stupid to tweak my own machine, therefore, it set up defaults that I CANNOT change, things like processes vs. disk, priorities, all the things I was used to tweaking in a unix kernel to make a server machine, or a desktop machine.
#2 For some dumb reason, MS decided that the "registry" was to be an 'in memory' structure and *ONLY* gets written to disk on a clean shut-down. (you will notice that most software REQUIRES a re-boot after install, and this is WHY). There isnt even a 'sync' process (like unix provides) to periodically write the registry to disk. The longer you leave a windoze machine up, the more risk you take!
#3 MS assumes you are going to turn your PC off every night, (thereby flushing the registry AND removing the chance of memory leaks "spell that bugs"). Its Plain CRAZY to assume ALL users will shut down every night, in this day and age, MANY people leave their machines up UNTIL they CRASH!
#4 MS assumes you are going to CONTINUE to pay $89 to $199 for EVERY upgrade forever while they "dis-continue support" for older releases FORCING this on you!
#5 Newsflash! They are trying to tighten the grip even more! Check This out

Enter Unix

All good operating systems that utilize cache for disk and processes, need to write that data back to disk. They also require CLEAN shutdowns!
Unix was MADE to be up 24x7. My unix machine is typically up for 30 to 60 days, and I have heard of machines that are up for 2 YEARS!!! (Try THAT in an MS environment!)
Unix knows ALL about security, it was built in long ago, no longer will you have e-mail viruses attacking e-mail, or attachments hurting you. No IIS security holes will hit your Apache web server.
You see, MS added a little something to ALL their applications, called VBA (Visual Basic for Applications) that while nice, opened a BIG hole. It allows me to write a simple macro in excel (or word, or access), that autoruns (meaning when you first open it) that can delete the ENTIRE contents of your hard drive! and there is no final question! it just DOES it!.. this is how dangerous these things can be!
Having PCs that just run and run, with no crashes (one server here made 150 days before a human accidently turned off the power strip), is very nice indeed. Knowing that no software can EVER be installed unless I know about it (root privvies) is even better. Also, a Side benefit to this is no visitors to our house can "install" anything when here. You know the drill: a friend comes over and wants to "check their e-mail", and then you find out they installed Quicktime or something! This cannot happen under unix, users are users and root is root (Admin account)