Most have reported better performance with Virtual Iron using File I/O. I don't have much information with XEN performance there are some using this with Block I/O from past cases and seem to do well.
There is a post from one of the members using XEN from this link, perhaps they can provide additional information on this subject. Would be good to know.
Concerning the 4060c we do not have any tests with this HBA and is not yet listed on the HCL so this would only be used as NIC and not for TOE support.