Move Windows 7 to SSD? try Windows 8

Thinking of buying a solid state drive (SSD) to speed up your PC? It is usually recommended to move Windows, rather than data, to the SSD. But it is a bit of a kerfuffle, and there is some risk. See for example https://www.techspot.com/community/topics/transfer-windows-7-from-hd-to-ssd.171854/ . So how about this idea? Get Windows 8 and put it on the SSD, and leave Windows 7 alone on the hard disk drive (HDD). Alternate between the two as desired.

Currently, July 2012, Microsoft is offering a free copy of the Windows 8 Preview Release; actual release of Windows 8 is expected around Oct 2012. So here's an idea. Note: I haven't done this yet, so please, anyone who else, confirm or correct each detail.

Buy an SSD
Add it to your PC - do not remove the HDD
When you boot, it will be assigned the next available letter, e.g., E:
Download Windows 8 (currently at http://windows.microsoft.com/en-US/windows-8/download) kit
Install Windows 8 on your SSD
Reboot PC, go into BIOS, tell it to boot from E: instead of C:
If it works, you are running Windows 8
If it doesn't work, or if at any time you hit a wall and need to go back to Windows 7, switch in the BIOS from E: to C:
For next few months, don't install anything other than Windows 8 on the SSD
As each new release of Windows 8 is out, boot from C:, erase the SSD (if necessary), and install new version of WIndows 8 there
When Windows 8 is final, install the final version to your SSD, and then consider adding other things to the SSD

Questions:
Can all PCs switch back and forth booting between C: and E: ?
Will all (or most) programs work if the operating system is moved to a different drive?
Any other risks or gotchas in this approach?
 
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