The 815 chipset is available for nearly one year now, that's why I would not forgive any problems with system stability. Fortunately, both the Azza 815EXP and the Asus CUSL2-C Black Pearl ran perfectly stable as well as fast. There is still some room for improvement with the Azza board, as it is a bit behind the competitor from Asus. Both motherboards are equipped with standard hardware. Azza features a sound system, which is not available on the Asus board. Asus, in contrast, has a sixth PCI slot that can of course be used for a sound card.
The drive bay modules left a mixed impression. AOpen's Dr. LED is basically a good idea, but I doubt that I would abandon a drive bay in order to have those LEDs and a special storage space for 10 CDs. In times of hot CPUs, graphics cards and hard drives I prefer to keep my system as empty as possible, since every component will heat up and contribute to high system temperatures.
Azza reduced their Azza-Up only to functions that are really important. In my opinion that means a line in and line out plus one or two USB ports and maybe an IR port. The Azza-Up brings all three audio jacks and two USB ports to the front of the PC, which could e.g. be used for a digital camera.
The most sensible as well as practical solution comes from Asus. The iPanel provides all kind of interfaces - depending on the version you buy (basic or deluxe). There are also versions with IR port available. Though the iPanel is the most expansive add-on, it is by far the most valuable.