I have not, but I've had very good success with Echo .095 string. Very tough, doesn't break easily, cuts through thick weeds, and it's readily available at Home Depot. The only thin I don't like is that it's bright orange, so when it does break or is cut when it's lengthened, the pieces are easy to see on the lawn.
Others have reported good results with Rino-Tuff as well.
I've heard the EGO Chainsaw bar and chain is made by Oregon. Not sure what else of theirs is made by them, but I wound up getting Oregon's .095" spiral twisted Gatorline, same shape as the OEM orange stuff that came on my EGO 15" Brushless trimmer. I liked the way the EGO's twisted line performed so much, that I tried to get as close as possible to it. Never tried any other shapes with the EGO trimmer, but interested in how others perform as well.
Oh yeah, and I got it in dark green, so it's not an eye-sore when some breaks off in the yard.