I personally have used the Eplison, Prophecy and MX2 (in addition to older options).
The thing is I'm hooked on is the lockup feature of a cable driven rest. I love that i can lock it all the way up and not think about it. The AAE prophecy was nice and heavy duty (outside of the flexy fork) but the adjustments were so rudimentary compared to the QAD. No click. Same with the Epsilon, the QAD seemed way tighter and had super fine micro adjustments. Crazy fine and love that I can do two clicks, see if it tightens my group and move it right back.
The thing with the MX2 integrate option is that is it seems over complicated to attach. I can see that not being that robust. It doesn't seem like it would be as sturdy as a normal MXT mounted.
Now the R7 looks to have improved and fixed all my concerns. It seems like the best limb driven on the market - TBD