IDE is legacy. The sooner it is gone the better, IMHO. I am really surprised at how slowly SATA has penetrated the marketplace.
A friend of mine who has been using personal computers since the late 1970’s recently built a new Athlon 64 machine for his father. It had a really strange problem – it took almost a full minute to boot up into Windows XP. We thought it was very strange since much less powerful Athlon machines were booting in about 15 seconds. Eventually I discovered that he installed the DVD-RW drive as a slave, but it was the only device on the channel. It worked just fine as a slave! Windows didn’t show any errors. But it booted up very quickly after changing it to master.
Even smart people make mistakes. SATA would have eliminated the possibility of this error. It has the potential to save people a lot of headaches, and it should also be cheaper to implement than IDE (with sufficient manufacturing volume.)
I’ve never really looked at SATA for the performance advantages. Those don’t exist yet (arguments about TCQ aside), and probably won’t for years.