To re-jump back on this bandwagon of stabliness; my Gold Line has a little flip but finishes straight. My Opto can hold a flat line the entire distance but has the mildest of fades. If powered up and with less than perfect form, the Gold Line can flip over and ditch itself into the ground at 240 feet. The Opto will track right and go about 330 feet before finding ground. For me, while they are not nose (up or down) sensitive like my Rivers, they are more anhyzer sensitive than my TeeBirds.
I am finding that I am spending more and more time with my TeeBirds again (I went through this same phase with my Rivers), but I am not abandoning the Saints yet. I really like the flip in the Gold Line and for the Opto I like when I get it right that it stays flat, tracks a little to the right, but still ends up on my line, and with tremendous distance.
If any of them goes significantly to the right, it is because of poor form, not because of the disc. I can see the comparison to a Sidewinder if you happened to get one of the least stable Saints, especially if your can throw with power, but for me I am sticking with my comparison of between a TL and TeeBird.