Shapeshifter has a far more intuitive GUI, is easier to set up and use, and seems slightly faster on my systems. Basilisk II does have a couple of features that were missing from Shapeshifter, but it's still not really worth using except on a PC in Linux. I even prefer Shapeshifter to Fusion, which again has a worse GUI, is harder to set up, but has a couple of extra features missing from Shapeshifter.
With the amount of extra support and all the other people already using it who can give advice, it's definitely worth just using Shapeshifter, although give the other two a try and come to your own conclusions.
