When two boats share the same hull type — in this case both the Malibu 21 LSV 2009 and the Malibu Response TXi 2013 are modified vee designs with fiberglass construction — 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?
The power gap is worth calling out. Rated to 450 hp, the Malibu Response TXi 2013 has a 50-hp advantage over the Malibu 21 LSV 2009's 400-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Malibu 21 LSV 2009 carries 46 gallons versus 4 gallons in the Malibu Response TXi 2013. 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 21 LSV 2009 is rated for 12 passengers, while the Malibu Response TXi 2013 caps at 9. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Malibu 21 LSV 2009 could be the deciding factor.
Bottom line: Choose the Malibu 21 LSV 2009 if your priority is putting more people on the water — it handles 12 passengers and at 21,0 ft it has the deck room to back that rating up comfortably. The Malibu Response TXi 2013 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 9 that costs less to run day-to-day.