I actually have the 686 I guess lol the 666 is 66.6 inches where mine is 68.5 inches. The hybrid swings like a dream. Any hybrid. This gun impaler built is awesome though. For as long as it is, it moves through the water very nice. I've taken a 170lb yellowfin, and tracked 6 wahoo so far with no problem. I've had zero experience with the Mach 5 tho, so I can't compare them. I can only tell you this gun swings better than my islander that's a fact.
