Both the Mariah G23 2010 and the Mariah R21 2011 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 G23 2010 at 23,0 ft versus Mariah R21 2011 at 21,4 ft. Weight tells a clearer story for trailering families: the Mariah G23 2010 tips the scales at 4 500 lbs - 1 100 lbs more than the Mariah R21 2011 at 3 400 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 share a closely matched power ceiling - 320 hp for the Mariah G23 2010 and 300 hp for the Mariah R21 2011. Real-world performance will come down more to which motor is actually bolted on, its load at the time, and whether it's a 4-stroke or 2-stroke setup. Fuel capacity breaks the other way: the Mariah G23 2010 carries 57 gallons versus 36 gallons in the Mariah R21 2011. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
For family outings this is probably the sharpest distinction between the two. The Mariah G23 2010 is rated for 12 passengers, while the Mariah R21 2011 caps at 10. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Mariah G23 2010 could be the deciding factor.
Bottom line: Choose the Mariah G23 2010 if your priority is putting more people on the water - it handles 12 passengers and at 23,0 ft it has the deck room to back that rating up comfortably. The Mariah R21 2011 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 10 that costs less to run day-to-day.