This was a pretty poorly written article... Rapid Start is not about suspend, it's about hibernate (suspend-to-disk). Or, well, a hybrid of thereof, where suspend-to-RAM goes into hibernate after some time passes (or the battery becomes very low). So it's generally an interesting idea. And it's nice that it's already available on Linux (in a sense).
What's not nice is that it's all handled by the firmware. Firmware tends to be horrible as is, UEFI even more than usual. So I could see this going very wrong in many ways. There's also a need for a special partition, which is too bad, as swap is pretty much made for the same purpose.
If you hibernate on linux, how would you boot to another OS?
Hibernate powers off the PC entirely. When you power it up, you get the bios, and then grub (or your bootloader of choice), where you can restart the hibernated OS, or start an other OS, or restart another hibernated OS.
I've done that in the past, but had many issues with the filesystem shared by the two OS, probably because the OS doesn't expect a filesystem to be changed while it hibernates (doesn't unmount, maybe even doesn't write all from cache, etc..).
I would like to point linux distros have a hybrid mode, you can usually invoke it from console with pm-suspend-hybrid
This command copies ram to disk, but instead of shutting down it goes suspend.
If power has not been lost (battery has not ran out), you can come back instantly. But if power has been lost, you did not lose anything and it performs the regular (albeit slower) power from hibernate situation (copy from disk back to ram).
This leaves Intel method unnecessary. Shouldn't hurt to just make your bios boot faster by skipping unnecessary stuff (ie. coreboot style).