When two boats share the same hull type — in this case both the Sundance NX21 2010 and the Sundance SV205 2008 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?
Size is the most obvious dividing line here. The Sundance NX21 2010 measures 21,1 feet overall (2010), giving it roughly 19,1 additional feet of deck space compared to the Sundance SV205 2008 at 2,0 feet (2008). At 185 lbs and 185 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.
The power gap is worth calling out. Rated to 200 hp, the Sundance SV205 2008 has a 85-hp advantage over the Sundance NX21 2010's 115-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Both carry nearly identical fuel loads — 45 gal and 45 gal — so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Sundance NX21 2010 is rated for 8 passengers, while the Sundance SV205 2008 caps at 6. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Sundance NX21 2010 could be the deciding factor.
Bottom line: Choose the Sundance NX21 2010 if your priority is putting more people on the water — it handles 8 passengers and at 21,1 ft it has the deck room to back that rating up comfortably. The Sundance SV205 2008 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 6 that costs less to run day-to-day.