I have used a Delta, similar to Landshark for almost ten years.
My son has a Great Northern on his Predator, with the little knobs that thread in the bushings, and it works great.
It will end up being a personal decision. I have tried the Great Northern on my bow, and found it to be very easy to remove for transport in a case, without crunching feathers. I prefer the Delta, because of the looks, and a greater space between the two points of contact with the arrows. I feel it quiets the arrows, and does not allow the fletching to touch and rattle together. My son says he likes his Great Northern because of the looks, and it keeps his arrows quiet, and seperates the fletching. :D
Congrats on your purchase of a great bow.