The biggest issue most will face using Solaris 10 x86 is problems with video cards, not unlike Linux of the mid 1990's. Even using a supported card does not necessarily mean you will get a display without some work. Prior to the addition of the Xorg server Sun's X Server was Xsun, which only worked with a small selection of video cards. Sun used ATI as the video chipset of choice for their low-end and midrage video hardware, and I have used ATI cards successfully since Solaris 7 on various x86 machines.
Of the two x86 machines I installed Solaris 10 6/06 on I had problems with the Gateway GT5056 if I used the motherboard integrated nVidia GeForce 6100 graphics and the Pentium IV machine with the ATI Radeon AGP card. The Solaris installer recognized both cards correctly but upon the first reboot I got a 640x480 screen. In the case of the Gateway machine I ended up using VESA mode 1024x768 256 colors. The Pentium IV machine even though it was configured for 1280x1024 and 32-bit color I got a 1024x768 display. Prior to this using an ATI video card in an x86 machine was a "no brainer", now it seems that using a nVidia card appears to be the no effort configuration.
An unexpected annoyance
When initially installing Solaris 10 6/06 using CD media I found myself at a similar point in the 1/06 Beta, and that is an issue where once you install Solaris 10 and reboot you are asked for CD's 2 through 4 (or 5 in the case of 6/06) a second time! During this process no files are actually installed, you are prompted for the CD's and you click Exit after each one until you have used all of the CD's and reboot the system. For those of us who use systems that do not have DVD drives (mainly older SPARC machines) and do not want to go through the trouble of setting up a JumpStart server, this is more than a little painful.
I reported this as a bug during my testing of Solaris 10 1/06 and I am a little disappointed that the issue has yet to be fixed. Now I understand Sun's position in pushing people to use DVD as the media of choice for installation but many of us still have SPARC and x86 systems that have CD ROM drives, and replacing them (especially SCSI systems) is not cheap or practical. This is one thing that should have been fixed in the 1/06 Release and Sun should not have allowed this to slide.
With ZFS, Zones and Containers, Sun takes Solaris 10 to a whole new level of functionality for businesses looking at consolidation through virtualization, a new filesystem with advanced capabilities and fine grained resource controls. The ability to manage ZFS filesystems is eased by including web based administration as well as the traditional command line tools. The only thing that would make ZFS better would be the ability to revert to the individual file level, that would make Solaris the choice for building "do it yourself" near line storage systems.
As the SATA framework matures, I hope that Sun provides support for more than high-end cards and older controller logic. Sun for a long time has treated IDE as the low-end drive interface for those who "can't afford a SPARC" and are willing to suffer with poor disk performance in order to use a good OS on Sun hardware (SPARC initially and now x86). Since I haven't had the opportunity to use a Sun x86 system that supports SATA I cannot say how well it works, the only Sun x86 systems I have ever used is the V20Z which ship with SCSI disks. I would definitely like to get my hands on one of the SPARC machines using SATA and run it through some benchmarks to see what I can get out of it as opposed to a similarly configured SCSI system.
With X on x86, Sun in my opinion has some work to do. While providing the capability to use more cards is good, the ability to easily configure a display is just as important. This point alone will dissuade neophyte users more than anything else. As a system administrator I am aware of kdmconfig and how to use it, and also know how to use the "time honored" configuration of Xorg which is a throwback to the Linux days of the mid 1990's. For those coming from Linux where the display is automatically configured, they will see this as a step backwards for Solaris. I hope Sun decides to put more effort into automatic configuration of X and not leave it in its current state.
Sun has put forth a great deal of effort into developing Solaris 10 6/06 and bringing new and powerful features to users and system administrators. This Release has a few more issues than previous Releases I have used and tested, and I hope that what I experienced is just a one time anomaly. Other than the CD install issue, the SPARC machines I used 6/06 worked without incident. None of the issues are "show stoppers", just annoyances that I experienced mostly on x86 systems.