No better or worse, they are still too dissimilar to count on anything, and the 9020 is much newer.  It may be able to load drivers it needs on the fly, but probably not.  You would also have to manually add Vista to Windows 7's bootloader.  Also, you still would not have the license/right to run your OEM Vista on any other computer (downgrade rights would allow you to run Vista Business only as a downgrade from Windows 7 Pro only).
Hi, I just received a new xps 8700 mini-tower with windows 7. - Can I simply unplug the vista hdd from a optiplex 755 and add it to the new xps machine as a second hdd? - will this automatically create a dual boot option? 
How to migrate a Vista hdd to a Windows 7 computer?