Well, I am working through the installation of Solaris 9 on my new Ultra5, and I am reflecting on how complex this installation really is.
As you know, I have already learned and installed multiple different versions of Linux. (In fact this server is running on Gentoo Linux, which I migrated to from RH 8.0) It was a challenge learning that OS, but I felt some measure of comfort since I understood the underlying hardware. I have built many computers over the years and feel comfortable installing and removing hardware and configuring the BIOS.
My new Sun system is completely different. I am both learning a new OS and a new hardware platform. The interesting thing about Sun hardware is that their BIOS is totally different from that on PCs. Basically you boot to a basic command prompt and then enter commands there. It is a challenge because I have no idea what the commands are! Well, I am learning.
The other interesting thing is that there are definitely some commonalities between Linux and Unix. I am just beginning to scratch the surface of Solaris and fortunately my existing knowledge is helping.