The Marathon DN 13 2013 is a deep-V design and the Marathon Seneca Utility 14 2008 is a modified-V design, so you're likely deciding between two noticeably different on-water experiences. Hull type shapes everything from ride quality and fuel burn to dock handling and resale trajectory.
On paper these two are close siblings in the size department - Marathon DN 13 2013 at 13,0 ft versus Marathon Seneca Utility 14 2008 at 14,0 ft. At 150 lbs and 218 lbs respectively, both sit in a similar weight class - either should pair comfortably with most mid-size SUVs and half-ton trucks, though always confirm your specific tow rating with the motor added.
Both boats share a closely matched power ceiling - 15 hp for the Marathon DN 13 2013 and 25 hp for the Marathon Seneca Utility 14 2008. Real-world performance will come down more to which motor is actually bolted on, its load at the time, and whether it's a 4-stroke or 2-stroke setup.
For family outings this is probably the sharpest distinction between the two. The Marathon Seneca Utility 14 2008 is rated for 5 passengers, while the Marathon DN 13 2013 caps at 4. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Marathon Seneca Utility 14 2008 could be the deciding factor.
At this size, power-to-weight ratio matters more than outright horsepower. The Marathon Seneca Utility 14 2008 comes in at 9 lbs per hp versus 10 lbs per hp for the Marathon DN 13 2013. The lower the ratio the more explosive the acceleration - meaningful on a short RIB where bursts of speed, quick planing, and agility in surf or tight waterways define the experience.
Bottom line: Choose the Marathon Seneca Utility 14 2008 if your priority is putting more people on the water - it handles 5 passengers and at 14,0 ft it has the deck room to back that rating up comfortably. The Marathon DN 13 2013 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 4 that costs less to run day-to-day.