Both the Mariah G19 2010 and the Mariah G21 2012 are modified-V designs, the first built in fibreglass and the second in aluminium, 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 - Mariah G19 2010 at 19,3 ft versus Mariah G21 2012 at 21,4 ft. Weight tells a clearer story for trailering families: the Mariah G21 2012 tips the scales at 3 600 lbs - 700 lbs less than the Mariah G19 2010 at 2 900 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 300 hp, the Mariah G21 2012 has a 80-hp advantage over the Mariah G19 2010's 220-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Both carry nearly identical fuel loads - 38 gal and 35 gal - so range won't be a tiebreaker here.
Both boats are rated for 10 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 Mariah G21 2012 at 21,4 ft is the right call if deck space, comfort, and entertaining are top of your list. The Mariah G19 2010 at 19,3 ft wins on trailering ease, likely lower purchase price, and simpler docking - a solid choice for a buyer who wants more boat for less money.