SmartTrac from Watts Radiant

Does anyone have any experience with SmartTrac from Watts Radiant?  (See here <a href="http://www.wattsradiant.com/products/SmartTrac/">[u][color=#0066cc]http://www.wattsradiant.com/products/SmartTrac/[/color][/u]</a>). Building a house in a Zone 5 location - looking at different radiant panels for the first and second floor (basement will put tubing in concrete).   About 4,500 sq/ft above grade.   Cost difference between Warmboard and SmartTrac product is alot.  Realistically we could go with Warmboard, but we would have to save on insulation costs and use fiberglass.   The other option is to go with SmartTrac and use a spray foam insulation.   I've got a very good general contractor and HVAC subcontractor, but neither have experience with Warmboard or SmartTrac.  I realize that SmartTrac does not have an aluminum layer to it, so that it will require more tubing and slightly higher water temps.  Despite the additional labor and materials, SmartTrac is still much, much more cost efficient. Will be using mostly engineered wood flooring over whatever panel is used, along with a much smaller amount of tile.  Need to know whether the aluminum conductive layer makes that much of a real world difference.  If anyone has any experience with SmartTrac, or other MDF or similar panels, comments about the performance would be most appreciated. Thank you.