Matching a modified vee Klamath 15 ft. Advantage S 2008 against a deep vee Klamath 21 ft. Baja 2010 means you're likely deciding between two genuinely different on-water experiences. Hull type shapes everything from ride quality and fuel burn to dock handling and resale trajectory.
Size is the most obvious dividing line here. The Klamath 21 ft. Baja 2010 measures 21,3 feet overall (2010), giving it roughly 6,3 additional feet of deck space compared to the Klamath 15 ft. Advantage S 2008 at 15,0 feet (2008). At 35 lbs and 115 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 150 hp, the Klamath 21 ft. Baja 2010 has a 105-hp advantage over the Klamath 15 ft. Advantage S 2008's 45-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load.
For family outings this is probably the sharpest distinction between the two. The Klamath 21 ft. Baja 2010 is rated for 8 passengers, while the Klamath 15 ft. Advantage S 2008 caps at 6. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Klamath 21 ft. Baja 2010 could be the deciding factor.
Bottom line: Choose the Klamath 21 ft. Baja 2010 if your priority is putting more people on the water — it handles 8 passengers and at 21,3 ft it has the deck room to back that rating up comfortably. The Klamath 15 ft. Advantage S 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.