Service Product (Download from R3 or Create in CRM)

Hi, we are implementing service with R3 billing and were trying to determined if to download the service products from R3 or to create them in CRM and then upload them. Currently we have service products in R3 however it's not clear if it's a good idea to keep them now that we are integrating CRM.

From what we know, service products need to be mapped between CRM and R3 so that R3 billing can take place. In order to accomplished this, we can download them from R3 to CRM, but they are created as products of type material and not as services. If this is so, we assumed that we are loosing part of the functionality meant for service products.

On the other side, if we create them in CRM and upload them to R3 then we seem to have the integration and keep their functionality in CRM.

If this approach correct or actually it's a good idea to download the service products existing in R3?

Thanks