Using different AV vendors on servers and PC's

Hi,

Obviously not on the same machine, but using different vendors on PC's to what you use on servers.

My client currently use Sophos for clients machines and are looking at replacing Kaspersky on servers. 

I suggested Sophos, but it was mentioned that it may be a good idea to use different vendors asv iruses are more likely to be picked up? 

Is this a good enough reason not to consider Sophos for servers?

Cheers