I believe you'll get no problems with "porting yourself" to the linux especially if you learn something about *nix-like system.
What can I say comparing PC OSes I've met in my carier (DOS, Windows, CPM): it is probably the most comprehensive system.
I am not surprised that you dislike the RH, Mandrake, etc. I believe your opinion about Slack will be the same. My feelings were the same: a lot of directories, scripts, services. But no way to get study how the system is really working.
I believe the best way (at least for me) to learn the system - which as a matter of fact is a sum of the kernel and a lot of small utilities - is to built up your own system.
So my advice is to pay attention onto LFS
It willl give you the outlook to the matter what is the "core" of the system and what should be seen as (usable but anyway) extensions. It will allow you to learn the dependencies between all the parts of the system. You will also:
1. get the system with all the files (configurable ones, executables, etc) placed in the directories you choose and are known for you - you'll get no dobts where a file is;
2. avoid a lot of (in my opinion) unreadable scripts which are in standard distros (on the other hand they must be so unreadable since the standard distro has to assume a lot of possible PC configurations)
3. save a lot of disk space usually wasted by the utilities you will never use
4. get really FAST OS (mine is starting within 20sec) especially if you compile the sources with your CPU specific options
5. avoid a lot of surprises (very important if you are creating server) that something "mysterious" is done by system
6. many, many more... (I could give you a hundreds argues more)
Regarding the programming matters: comparing with Windows you'll find out that the system's libraries are CONSISTENT. There is no "similar" functions - in Windows I've always considered which function I should to use and why just 'this' one. There is no 'hidden' functions (since it is Open Source system) nor processes. In case of problems you will be able to get info not only HOW to solve your problem but also WHY you should solve it in supposed way (in Windows in many cases it is impossible since it is documented badly in many places).
So good luck.