DH Aether is the softest clear I've worked with and reformulated Lauscha clear is the stiffest. Effetre clear is somewhere in between but sucks in terms of quality and clarity.
I love Aether for its softness and ease of use for encasing, but the negatives are that it turns certain silvered glasses green, and (at least for me) I get skid marks on my beads from laying them on the kiln floor. I don't get that problem with any other clear, but no matter what, when I encase a bead with Aether, the floor of my kiln will leave a mark on my encasement. I've thrown away alot of beads because of this
My kiln is set at 940 and I usually rest beads on a kiln rack at first, and then move them to the kiln floor . . . and still, Aether-encased beads wind up with a mark on them.
For the Lauscha clear . . . I like the clarity and quality because it's far superior to Effetre, but the stiffness makes it more difficult to use for encasing larger beads. I use the "big blob" method to encase large beads and the Lauscha glass is harder to use for this.
BUT, I'd rather have a more difficult glass to use than to use effetre and have all of my beads wind up with hazy crap on them.