The Larson LX 205 S I/O 2013 is a deep-V design and the Larson LX 620 O/B 2012 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.
Size is the most obvious dividing line here. The Larson LX 205 S I/O 2013 measures 21,1 feet overall (2013), giving it roughly 4,9 additional feet of deck space compared to the Larson LX 620 O/B 2012 at 16,2 feet (2012). Weight tells a clearer story for trailering families: the Larson LX 205 S I/O 2013 tips the scales at 2 700 lbs - 1 550 lbs more than the Larson LX 620 O/B 2012 at 1 150 lbs. That difference is meaningful if you're working within a half-ton or three-quarter-ton truck's tow rating, especially once you factor in a motor, gear, and fuel.
The Larson LX 620 O/B 2012 tops out at 90 hp. Engine specs for the Larson LX 205 S I/O 2013 aren't listed - confirm with a dealer before selecting an outboard.Fuel capacity breaks the other way: the Larson LX 205 S I/O 2013 carries 30 gallons versus 19 gallons in the Larson LX 620 O/B 2012. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
For family outings this is probably the sharpest distinction between the two. The Larson LX 205 S I/O 2013 is rated for 8 passengers, while the Larson LX 620 O/B 2012 caps at 6. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Larson LX 205 S I/O 2013 could be the deciding factor.
Bottom line: Choose the Larson LX 205 S I/O 2013 if your priority is putting more people on the water - it handles 8 passengers and at 21,1 ft it has the deck room to back that rating up comfortably. The Larson LX 620 O/B 2012 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 6 that costs less to run day-to-day.