In terms of the price: think about how much you spend on strings and instrument and how comparibly small money a rosin is, even though it has such a strong impact on your play and your sound.
I am using the softest version of Leatherwood. I suppose it is the 20 which is recommended for the use in old music/gut strings, because it is extremly sticky (similar to pops in that sense). But: I use it with extremly responsive Gerold Genssler strings that react on the smallest movement of the bow quickly and extreme which you might think demands for the opposite of what plain gut needs. So that is also what I love about this product. I have the overtones, the softness, the beauty, the ability to modulate but I also have the extreme stickyness and grib that I need for the attack and the control. So what else do I need?!?!
Just one thing: the soft version has a very weird texture, you would never expect a clear sound from it. And one funny observation: when you put a lot of it on the bow, the first 2 or 3 minutes, it is like oil, extremly slippery... and then it get stickier and stickier!