quite an interesting system. I have not seen the under current before,
I don't think there is going to be much difference in yield etc based on the two systems you mention. They are so very similar in the way they work that the most deciding factor will probably be your grow skills but I could be totally wrong as I have never used the Under Current. I have however used Recirc DWC..
Are you thinking of buying one of the Under Currents?