Never again Solaris
We've been using both Solaris and Linux on our servers. And I have to admit, I am not impressed by Solaris. Guess what servers crapped out when power went down (the filesystem was all corrupt). I have to admin it was using UFS, but again guess on which server I saw Oracle reporting corrupt blocks (on an x86 with Solaris and ZFS). Upgrades are headache, lack of official software repositories, installation problems even on Sun Servers. We are using Oracle a lot and deploying on ASM does the job perfectly. When you want to install an application (that is not int the top 20 most pupular applications) guess on which OS you have to bang your head to compile it !? I will try to stay away from Solaris, except headaches we never got something good. And with the binary compatibility your areimpacted if you write really low level code (drivers and stuff), so zvonr dont spread you FUD around.