Both are super wide and it depends on what housing with 67mm threads you plan to mount it on plus the camera inside. Both have an optical polycarbonate dome which minor scratches (inevitable in time) will fill in with water once submerged.
I have the Fantasea UWL-09f plus the QRS quick bayonet system which is great for "burping" the lens underwater to remove any air bubbles on the rear element and housing port front element. Full disclosure; I'm a Fantasea and Ikelite dealer but use the same equipment I sell.
The Kraken is a bit heavier (1433 grams) compared to the Fantasea UWL-09f (1033 grams) and underwater both lighten up a bit due to the ai trapped in the dome but not a lot.
The Kraken says full zoom through and the Fantasea allows some (1/2 - 2/3 of a camera's focal range?)
I'm not sure you'll be able to zoom as an example a Canon G7X II camera's 24-100mm lens all the way through and have it focus without edge blurring, etc. The optical challenge of a 100mm telephoto to focus on a super wide group of optical elements seems almost impossible.
Why you would even want to do that as it won't be any true macro close framing. Putting a WA lens on means you want to shoot wide scenics, big animals, dive buddies, etc.
Just one old guy's thoughts
haas