Both the Campion 650i SC 2009 and the Campion Allante 645i BR 2011 are modified-V designs, both built in fibreglass, so 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?
On paper these two are close siblings in the size department - Campion 650i SC 2009 at 23,0 ft versus Campion Allante 645i BR 2011 at 23,1 ft. Weight tells a clearer story for trailering families: the Campion 650i SC 2009 tips the scales at 4 210 lbs - 173 lbs more than the Campion Allante 645i BR 2011 at 4 037 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 375 hp, the Campion 650i SC 2009 has a 55-hp advantage over the Campion Allante 645i BR 2011's 320-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Both carry nearly identical fuel loads - 56 gal and 56 gal - so range won't be a tiebreaker here.
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: Performance buyers should lean toward the Campion 650i SC 2009 and its 375-hp ceiling. If fuel economy and quieter running matter more than top-end speed, the Campion Allante 645i BR 2011 with its 320-hp rating is the more economical daily driver.