Choice between 2 speaker cable types.

I would like to upgrade my speaker cables and I have been referred to two well known speaker cable companies. Straightwire and Cardis are the two recommended to me. Does anyone have any experience or input regarding these two companies and the two cable models suggested to help guide me in the right direction. Straightwire - Expressivo Grand vs Cardis - Cygnus series. 
I have a rather long run between my speakers (Focal Scala Utopia) and my amplifier (Mac MC302) at 26 feet so a proper quality cable has been suggested.
Thanks so much in advance for your assistance.
Andy