I purchased both Panther and Stihl chain at same time, I have ran both chains until the point of each chain showing signs of dulling and resharpened both, on an ECHO CS-2511WES 1/4 Drive Sprocket saw (purchased from chainsaw bars.co.uk also.In my opinion and preference would defo lean towards the Panther chain, (Sorry Stihl),
I found the Panther didn't dull as quick as the Stihl chain, although the Stihl chain seemed to take less with the file to sharpen than Panther, But still would lean towards Panther chain, again only my personal preference, Both chains are quality at the end of the day, Goes without saying the Customer service from Chainsawbars is second to none, always time to advise and explain any queries you might have with fast shipping to your door, defo my goto for carving supplies