Sorry this took so long, busy, busy . . .
I''ve always felt it far more important to have the front three speakers a perfect match. The surrounds should be as close as possible but it is not as critical. Part of it will depend on what you're matching up with. If you've got Sapphire XLs and or XLC up front, than yes, the Emerald XL would be a worthwhile upgrade. The look is of course totally different and many folks will prefer one look over the other. The Emerald XLs on brackets is probably a more conventional look. Does this answer your questions?