Both the Malibu Wakesetter 21 XTi 2005 and the Malibu Wakesetter VTX 2011 are modified-V designs, 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 Wakesetter 21 XTi 2005 at 21,0 ft versus Malibu Wakesetter VTX 2011 at 20,0 ft. At 3 400 lbs and 3 300 lbs respectively, both sit in a similar weight class - either should pair comfortably with most mid-size SUVs and half-ton trucks, though always confirm your specific tow rating with the motor added.
Both boats share a closely matched power ceiling - 400 hp for the Malibu Wakesetter 21 XTi 2005 and 410 hp for the Malibu Wakesetter VTX 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. Both carry nearly identical fuel loads - 46 gal and 48 gal - so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Malibu Wakesetter 21 XTi 2005 is rated for 12 passengers, while the Malibu Wakesetter VTX 2011 caps at 11. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Malibu Wakesetter 21 XTi 2005 could be the deciding factor.
Bottom line: Choose the Malibu Wakesetter 21 XTi 2005 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 Wakesetter VTX 2011 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 11 that costs less to run day-to-day.