Hasn’t Mac OSX got a Unix/Linux core?

It appears to me the biggest trouble with Linux, in all varieties, is that because of it’s nature of being developed by techies, they don’t understand user-friendliness because they know how to do it. I’m trying to get to grips with it but having only ever used Dos and various Windows incarnations, it’s quite a struggle.
I have a laptop with five operating systems on it (soon to be six, OS/2 Warp 4 for the hell of it) and by far the fastest is BeOS. As a virtually dead OS, there’s not a great deal of software about for it but it had great potential.
I’m playing with SuSE 8.2 and Mandrake 9.
So far SuSE appears easier.