Well XDCAM HD can be MPEG2@35Mbps, and many people compare that (some favorably, some not) to DVCProHD 100Mbps. You can edit in both, but I would choose DVCProHD over XDCAM HD to edit (In FCP anyway).
Regardless, if the footage is native XDCAM HD, you CAN edit natively, although many people digitize this to DVCProHD for editing ease. I would never convert footage to XDCAM HD for editing though.
Or, more likely, look around you edit room and see if any of your magazines have a headline on the cover like: “MPEG2@30MBPS is the next DV!”