Which feature are you particularly interested in? SSD caching is quite useless when directly using an SSD (which you definitely should if you build a new system, get something like a OCZ Vertex 3) and is implementend in BIOS. EZ smart response is the gigabyte marketing term for this. MemOK is a feature that's hardwired, it just checks that your memory is OK, and then some LEDs light up. But it doesn't prevent you from doing a memtest, and it also doesn't help with broken RAM. It's quite useless IMHO, too.
LanOptimizer is also quite useless and implemented as an application, which switches some profiles, but you're better off with the linux network stack in general, believe me.
EPU may be the only one that has a real value, as it can save lots of energy, i'm not sure to what extent that's supported by the kernel and drivers (it also needs graphic card driver support, f.ex.) But looking at this:
http://vip.asus.com/forum/view.aspx?boa ... uage=en-us seems it's not supported at all.
So to summarize, most of this new stuff are just gimmicks, and sadly makes the mainboards more error-prone. My experience comes from assembling and repairing hundreds of OEM-style custom built machines, all built from "quality" hardware, mostly Intel boards, but also Gigabyte and Asus boards.