Both nice, but for me, between the Blue Sky and the Supernatural, the Blue Sky hands down.
But talking "best", Eventide Space would also be in the running for me - more powerful, more flexible and programmable, but BIG. What the Strymon TimeLine is to delay, the Space is to reverbs.
kayDUB wrote
Don't know if it was just the particular demo I saw, but the supernatural's shimmer sounded darker, almost more "evil" in a way ?
Don't quote me, but I don't think the Supernatural is all perfect octaves, they've mixed a detune in there too to thicken it up.