I am making the big switch...well not really. Not yet anyways. I am doing a real live evaluation though.
So far, my overriding sentiment is that it is not hard to see why Microsoft still kicks enterprise software backside. It can be a very arduous process to set up a unix server and get everything running right if you have never done it before. While an experienced engineer might scoff and chalk it up to my relative inexperience...and that may all be well and good...at the end of the day I get to decide what we will be moving ahead with.
Consider: In order to install Apache on Unix from the binary you need to have a c compiler running. OK, go out and download GCC. Oh, in order to install GCC you need 'G Make'. Oh, in order to install 'G Make' you need GCC. Wait, what? In order to install either you need to pull all your hair out, light it on fire and do a hat dance around your office. Up to lighting your hair on fire, that was all true.
On to MySQL. Hard to complain too much, when you consider what they are giving you for free. But, don't you dare try to change your Root password by running a query against the database. There is a very specific command for this important first step.
After a day of knocking my head against the wall I have a unix machine running Apache, MySQL and PHP. After some configurations I am almost ready to install a PHP bug tracking solution and test it out.