GL beats in as much or more than any other premium plastic for me.
Totally agree. I was stunned as I read through this thread to hear all the people saying Gold Line doesn't beat in.
I have several Gold Line Rivers... the one I've used the most has beaten in to a super-understable turnover disc. I throw it even on a hyzer and it flips up, turns over, and goes right (RHBH throw). I bag it mainly for those dogleg-right holes where I absolutely need a turnover disc. Another GL River isn't as flippy... yet. I haven't used it as much, either.
I have three Gold Line Furys. The yellow one is my main one, and it has become a flippy turnover disc. The pink one is not as broken in, so it only turns over a little bit. I've replaced the Fury with the Star Sidewinder in my bag.
My Gold Line Flow is still somewhat overstable for me, but I haven't thrown it a lot. It's a good disc. My GL Saint is not the stable-to-overstable disc it was fresh out of the box. It's lost a lot of fade. If I used it more, I suspect it would get to near-turnover status.
Opto takes longer to break in, but it WILL break in (unlike Champion plastic, which seems to hold its flight characteristics forever). Opto feels like a gummy version of Champ, so I don't buy Opto discs too much... except the Pure. My Opto Pure has held serve fairly well, but is getting straighter and with less fade at the end.
I love the feel of Gold Line, but it does beat in, and in some cases a lot.