The Starcraft Marine Fishmaster 196 2013 is a deep-V design and the Starcraft Marine Islander 221 I/O 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 Fishmaster 196 2013 at 19,8 ft versus Starcraft Marine Islander 221 I/O 2010 at 22,5 ft. Weight tells a clearer story for trailering families: the Starcraft Marine Islander 221 I/O 2010 tips the scales at 1 858 lbs - 428 lbs less than the Starcraft Marine Fishmaster 196 2013 at 1 430 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 - 200 hp for the Starcraft Marine Fishmaster 196 2013 and 220 hp for the Starcraft Marine Islander 221 I/O 2010. 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 52 gal - so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Starcraft Marine Fishmaster 196 2013 is rated for 9 passengers, while the Starcraft Marine Islander 221 I/O 2010 caps at 8. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Starcraft Marine Fishmaster 196 2013 could be the deciding factor.
Bottom line: Choose the Starcraft Marine Fishmaster 196 2013 if your priority is putting more people on the water - it handles 9 passengers and at 19,8 ft it has the deck room to back that rating up comfortably. The Starcraft Marine Islander 221 I/O 2010 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 8 that costs less to run day-to-day.