The spec sheets list the Malibu Response 2005 as modified vee and the Malibu vRide 2008 as sv23 wake, so check how each hull rides in the conditions you use before you decide.
Both boats share a closely matched power ceiling - 400 hp for the Malibu Response 2005 and 400 hp for the Malibu vRide 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. Both carry nearly identical fuel loads - 35 gal and 35 gal - so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Malibu vRide 2008 is rated for 10 passengers, while the Malibu Response 2005 caps at 6. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Malibu vRide 2008 could be the deciding factor.
Bottom line: Choose the Malibu vRide 2008 if your priority is putting more people on the water - it handles 10 passengers and at 21,0 ft it has the deck room to back that rating up comfortably. The Malibu Response 2005 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 6 that costs less to run day-to-day.