The Odyssey Millennium 1909M 2005 vs Odyssey Millennium II 1701M2 2005 comparison sits squarely in the category of decisions where specs alone won't tell the whole story: intended use, storage, and long-term ownership costs all factor in.
On paper these two are close siblings in the size department - Odyssey Millennium 1909M 2005 at 18,0 ft versus Odyssey Millennium II 1701M2 2005 at 16,0 ft. Weight tells a clearer story for trailering families: the Odyssey Millennium 1909M 2005 tips the scales at 1 700 lbs - 300 lbs more than the Odyssey Millennium II 1701M2 2005 at 1 400 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.
Both boats are rated for 9 passengers - a good fit for a family of four or five plus guests. Comfort at capacity is another matter; the longer hull typically means more seat options and better weight distribution.
Bottom line: The Odyssey Millennium 1909M 2005 and Odyssey Millennium II 1701M2 2005 are closely matched on the specs that matter most. Test-ride both on the water you actually use, check current dealer pricing, and factor in long-term service access before you sign.