Both the Starcraft Marine 2100 2010 and the Starcraft Marine Limited IO 2000 I/O 2013 are modified-V designs, the first built in aluminium and the second in fibreglass, so the buying decision usually comes down to a handful of practical questions: how many people are you putting on the water, how far do you trailer, and what does your tow vehicle weigh?
On paper these two are close siblings in the size department - Starcraft Marine 2100 2010 at 20,8 ft versus Starcraft Marine Limited IO 2000 I/O 2013 at 20,3 ft. Weight tells a clearer story for trailering families: the Starcraft Marine Limited IO 2000 I/O 2013 tips the scales at 2 325 lbs - 610 lbs less than the Starcraft Marine 2100 2010 at 1 715 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.
Both boats share a closely matched power ceiling - 250 hp for the Starcraft Marine 2100 2010 and 260 hp for the Starcraft Marine Limited IO 2000 I/O 2013. 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. Both carry nearly identical fuel loads - 52 gal and 51 gal - so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Starcraft Marine Limited IO 2000 I/O 2013 is rated for 12 passengers, while the Starcraft Marine 2100 2010 caps at 10. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Starcraft Marine Limited IO 2000 I/O 2013 could be the deciding factor.
Bottom line: Choose the Starcraft Marine Limited IO 2000 I/O 2013 if your priority is putting more people on the water - it handles 12 passengers and at 20,3 ft it has the deck room to back that rating up comfortably. The Starcraft Marine 2100 2010 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 10 that costs less to run day-to-day.