The Starcraft Marine 1648 2013 is a flat-bottom design and the Starcraft Marine 1900 C 2010 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 - Starcraft Marine 1648 2013 at 16,0 ft versus Starcraft Marine 1900 C 2010 at 19,0 ft. Weight tells a clearer story for trailering families: the Starcraft Marine 1900 C 2010 tips the scales at 2 718 lbs - 2 423 lbs less than the Starcraft Marine 1648 2013 at 295 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 power gap is worth calling out. Rated to 200 hp, the Starcraft Marine 1900 C 2010 has a 165-hp advantage over the Starcraft Marine 1648 2013's 35-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load.
For family outings this is probably the sharpest distinction between the two. The Starcraft Marine 1900 C 2010 is rated for 11 passengers, while the Starcraft Marine 1648 2013 caps at 4. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Starcraft Marine 1900 C 2010 could be the deciding factor.
Bottom line: Choose the Starcraft Marine 1900 C 2010 if your priority is putting more people on the water - it handles 11 passengers and at 19,0 ft it has the deck room to back that rating up comfortably. The Starcraft Marine 1648 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.