The SouthWind 2010 L 2011 is a tri-hull design and the SouthWind 210 SD 2008 is a modified-V design, so you're likely deciding between two noticeably different on-water experiences. Hull type shapes everything from ride quality and fuel burn to dock handling and resale trajectory.
On paper these two are close siblings in the size department - SouthWind 2010 L 2011 at 20,1 ft versus SouthWind 210 SD 2008 at 20,0 ft. Weight tells a clearer story for trailering families: the SouthWind 2010 L 2011 tips the scales at 3 200 lbs - 700 lbs more than the SouthWind 210 SD 2008 at 2 500 lbs. That difference is meaningful if you're working within a half-ton or three-quarter-ton truck's tow rating, especially once you factor in a motor, gear, and fuel.
The power gap is worth calling out. Rated to 200 hp, the SouthWind 2010 L 2011 has a 85-hp advantage over the SouthWind 210 SD 2008'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 - 50 gal and 50 gal - so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The SouthWind 2010 L 2011 is rated for 10 passengers, while the SouthWind 210 SD 2008 caps at 9. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the SouthWind 2010 L 2011 could be the deciding factor.
Bottom line: Choose the SouthWind 2010 L 2011 if your priority is putting more people on the water - it handles 10 passengers and at 20,1 ft it has the deck room to back that rating up comfortably. The SouthWind 210 SD 2008 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 9 that costs less to run day-to-day.