Both the Triton Boats 215X 2009 and the Triton Boats DV 186 Liberty 2007 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?
The power gap is worth calling out. Rated to 300 hp, the Triton Boats 215X 2009 has a 125-hp advantage over the Triton Boats DV 186 Liberty 2007's 175-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 215X 2009 carries 50 gallons versus 40 gallons in the Triton Boats DV 186 Liberty 2007. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
Both boats are rated for 6 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 Triton Boats 215X 2009 at 21,0 ft is the right call if deck space, comfort, and entertaining are top of your list. The Triton Boats DV 186 Liberty 2007 at 18,0 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.