I am running one of my SeaSwirls with a ViaAqua 4900. I have had it running like that for about 18 months without a problem. I am, however, running it submerged, and since the pump is similar to both Rio and MagDrive I would be hesitant to run it externally. If you are looking for an external pump, you should go with the Dolphin. However, if you are going to be running it submerged you should definitely go with the ViaAqua.
Jim