Both the Triton Boats 192 Allure 2010 and the Triton Boats 21X2 SC 2009 are modified-V designs, the first built in composite and the second 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?
The power gap is worth calling out. Rated to 300 hp, the Triton Boats 21X2 SC 2009 has a 165-hp advantage over the Triton Boats 192 Allure 2010's 135-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Triton Boats 21X2 SC 2009 carries 53 gallons versus 40 gallons in the Triton Boats 192 Allure 2010. 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 Triton Boats 21X2 SC 2009 is rated for 6 passengers, while the Triton Boats 192 Allure 2010 caps at 1. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Triton Boats 21X2 SC 2009 could be the deciding factor.
Bottom line: Choose the Triton Boats 21X2 SC 2009 if your priority is putting more people on the water - it handles 6 passengers and at 21,0 ft it has the deck room to back that rating up comfortably. The Triton Boats 192 Allure 2010 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 1 that costs less to run day-to-day.