So, Why Do We Use SunSolve, Not the Download Center?
Philosophically, it would make more sense to use the Sun Download Center, which is more about downloading software products than Solaris patches. However, the Sun Download Center is organized around independent software products, which also tend to not be organized around hardware systems. Yes, Sun firmware is a single conceptual product category, but it is released independently for each hardware system. Sun chose to use SunSolve not because SunSolve is ideally suited for downloading firmware, but more because the Sun Download Center is particularly not well-suited for that purpose. There is also a long history of releasing Sun firmware via SunSolve, so until there is a clearly better alternative, Sun chooses to continue with the traditional SunSolve channel.