Worth upgrading surround speakers?

[Stephen84]

Evening all, I have been upgrading my system recently and I have a set of old Kef KHT2005 surround speakers, I know that these speakers are getting on a bit now and I'm wondering if buying a set of B&W M1's or something similar would be a worthy upgrade?

Thanks in advance : )

 

[Stephen84]

Bump, has nobody heard the old Kef speakers and the newish B&W M1's? Any input would be much appreciated as I won't have the chance to demo them before I buy them