Both the Malibu Response FXi 2011 and the Malibu Sunscape 21 LSV 2011 are modified-V designs, both built 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 - Malibu Response FXi 2011 at 20,0 ft versus Malibu Sunscape 21 LSV 2011 at 21,5 ft. Weight tells a clearer story for trailering families: the Malibu Sunscape 21 LSV 2011 tips the scales at 3 400 lbs - 200 lbs less than the Malibu Response FXi 2011 at 3 200 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 - 410 hp for the Malibu Response FXi 2011 and 410 hp for the Malibu Sunscape 21 LSV 2011. 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. Fuel capacity breaks the other way: the Malibu Sunscape 21 LSV 2011 carries 48 gallons versus 40 gallons in the Malibu Response FXi 2011. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
For family outings this is probably the sharpest distinction between the two. The Malibu Sunscape 21 LSV 2011 is rated for 14 passengers, while the Malibu Response FXi 2011 caps at 10. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Malibu Sunscape 21 LSV 2011 could be the deciding factor.
Bottom line: Choose the Malibu Sunscape 21 LSV 2011 if your priority is putting more people on the water - it handles 14 passengers and at 21,5 ft it has the deck room to back that rating up comfortably. The Malibu Response FXi 2011 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 10 that costs less to run day-to-day.