I've been searching for this disc for a year and was about ready to accept that it didn't exist and start emailing the manufacturers to make one.
I love this thing. K3 for me.
I play on courses with a fair bit of side hill greens and roll aways are my most hated thing in the sport. I've learned the trick is to match the disc to the angle of the hill when it lands. Finding a disc to do that has been tricky.
150 foot upshot to a side hill green. Throw something stable like a zone or harp and they come in on angle and have roll away potential. Unless you put anhyzer on it, adding another bit of complexity to the throw. Throw something less stable and it tends to be the type of disc with lots of glide. So you have to throw soft and tentative and bad things happen, wobble, missed line, not enough spin to meet your expected line. Either way you go, very touchy shot.
The Berg solves this. In K3 it is so straight, very little stall fade, just enough to be predictable. I throw it hard and it comes out of my hand fast and I think "Oh my god I just threw it 100 feet long!" but this thing is so lazy, moves through the air so slow and about the time it's getting to the basket it just gives up and drops down. It gets to the ground so fast once it runs out of steam it doesn't have time to really fade much at all.
The Berg lets me make firm confident throws without overshooting and its so straight I can match the angle of the hill with ease.
I love this thing.