They're a near-top predator that eats fish so I'd guess Wahoo would be somewhere in the vicinity of Albacore Tuna and Yellowfin (Chunk Light) tuna.
I'd like to try Wahoo, hear it's great, but I only eat what I catch and Wahoo are few and far between and mostly caught accidently off the Mid-Atlantic. I've never actually seen one.
If you have a bonefish grille near you they serve it. It's like turkey that tastes like fish.
I rate Wahoo as good as Mai-Mai (Dolphinfish). Light translucent pinkish flesh that turns snow white when cooked.
As they are a top line preditor, they will consume smaller fish and concentrate the mecury HOWEVER, like Mai-Mai they are faster growing and not as long lived and don't have the time span to collect as much mercury.
Wahoo are a BLAST to catch! Fast (about 10-12 knots) trolled lures and drift fishing live bait are normal methods. In the Gulf of Mexico they are normally in 200 plus feet of water. They hit baits at speeds up to 55 miles an hour and can pull 300 to 400 yards of line off a reel in seconds. A hard fighting fish many times the third "run" will be longer and tougher to stop than the first.
I have canned wahoo, if yer interested....