Topic v multiple Queues

Hi

I am thinking of using SB for sending messages to multiple locations (sites). There could be up to 300 sites.

I am using TOPICS and SUBSCRIPTIONS for this. So, I have one TOPIC and each message I sent to it has a SITEID property. The Subscriptions filter by the SITEID. Everything is working well. However, I was thinking if I should have used separate QUEUEs for the Sites instead of a TOPIC

Is there any compelling reason I should use separate queues instead of a topic and x hundred subscriptions?

Thanks for your help

Graham