I don't think Tagan is sold in the US anymore so it's hard to get much info, From looking around it seems the Piperock is Topower built, The Piperock II is built by Impervio, Quality wise the Impervio built unit is superior. As far as Tagan goes, You really want to look for the Piperock II, Or the Superrock series, They are built by Impervio and Enhance and are solid units. I would really stay away from the Topower units that are prevelant in much of the Tagan lineup.