Bubbleponics can also use air to move the water up the feed tube like a Waterfarm. That is ideal since it solves the extra heat problem associated with a w/p. Roseman uses water pumps with great success, though, so either will work fine. In any form of DWC, success depends on the temps you can maintain in the room and in the res. If it was a RDWC, top feed by bleeding off a small amount of nutes from the main pump would work great!
@Robby
I am very interested in this comparison. I would like to know how well the roots grow into the media as compared to straight DWC. The roots in DWC tend to run right past the hydroton in search of water/nutes leaving very little in the way of support for the plant. I am wondering if the added drip tube will cause the roots to be more entwined with the hydroton before they shoot out of the bottom. The added support would be nice. I also suspect the top feed will cause faster growth until roots hit the water. Another possible advantage would be less worry of saturating pucks or rockwool since the drippers do not saturate the center of the pot like submerging it does.
Thanks for the comparison and I hope you post back with your results.