99% don't boot to a cd? what?
PCs that I use generally have a boot menu. You hit F12 or ESC or whatever and a menu comes up asking you what you want to boot to (CD, Internal HDD, External HDD, etc).
On Mac you have to hold down the "C" key until it comes up which is a pain and even ejecting the CD is a pain. It doesn't come out immediately after you hit the button.
I don't think most users ever have a need to boot from a CD. The only time you would do it is to install an OS, which 99% of computer users never do, they just buy a new computer, they don't upgrade. (OK, maybe less than 99% but still a vast majority)
On the PC you still have to hit a key, I don't see the big difference. Taping a key once at the right time during boot up, or holding a key for 5 seconds. I don't know what you mean about ejecting a CD. On my Macs I just hit the eject key and it comes out.
Is rEFIt just for Mac? Is it free?
Yes (I think) and yes.
