The Crestliner C 1760 VS 2008 is a modified-V design and the Crestliner Sun Cast 2185 2009 is a pontoon 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 - Crestliner C 1760 VS 2008 at 17,0 ft versus Crestliner Sun Cast 2185 2009 at 20,0 ft. Weight tells a clearer story for trailering families: the Crestliner Sun Cast 2185 2009 tips the scales at 1 900 lbs - 925 lbs less than the Crestliner C 1760 VS 2008 at 975 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 - 60 hp for the Crestliner C 1760 VS 2008 and 60 hp for the Crestliner Sun Cast 2185 2009. 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 Crestliner Sun Cast 2185 2009 is rated for 9 passengers, while the Crestliner C 1760 VS 2008 caps at 4. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Crestliner Sun Cast 2185 2009 could be the deciding factor.
Bottom line: Choose the Crestliner Sun Cast 2185 2009 if your priority is putting more people on the water - it handles 9 passengers and at 20,0 ft it has the deck room to back that rating up comfortably. The Crestliner C 1760 VS 2008 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 4 that costs less to run day-to-day.