Both the Crestliner Backwater 1870 SC/CC 2010 and the Crestliner C 2070 VS 2008 are modified-V designs, both built in aluminium, 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 - Crestliner Backwater 1870 SC/CC 2010 at 18,0 ft versus Crestliner C 2070 VS 2008 at 20,0 ft. Weight tells a clearer story for trailering families: the Crestliner C 2070 VS 2008 tips the scales at 1 365 lbs - 190 lbs less than the Crestliner Backwater 1870 SC/CC 2010 at 1 175 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 - 90 hp for the Crestliner Backwater 1870 SC/CC 2010 and 90 hp for the Crestliner C 2070 VS 2008. 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 C 2070 VS 2008 is rated for 7 passengers, while the Crestliner Backwater 1870 SC/CC 2010 caps at 5. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Crestliner C 2070 VS 2008 could be the deciding factor.
Bottom line: Choose the Crestliner C 2070 VS 2008 if your priority is putting more people on the water - it handles 7 passengers and at 20,0 ft it has the deck room to back that rating up comfortably. The Crestliner Backwater 1870 SC/CC 2010 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 5 that costs less to run day-to-day.