Both the Xpress HD17PFC 2011 and the Xpress X21 2013 are modified-V designs, both built 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?
Size is the most obvious dividing line here. The Xpress X21 2013 measures 21,3 feet overall (2013), giving it roughly 4,3 additional feet of deck space compared to the Xpress HD17PFC 2011 at 17,0 feet (2011). Weight tells a clearer story for trailering families: the Xpress X21 2013 tips the scales at 1 580 lbs - 900 lbs less than the Xpress HD17PFC 2011 at 680 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 150 hp, the Xpress X21 2013 has a 60-hp advantage over the Xpress HD17PFC 2011's 90-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Xpress X21 2013 carries 30 gallons versus 15 gallons in the Xpress HD17PFC 2011. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
Both boats are rated for 4 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 Xpress X21 2013 at 21,3 ft is the right call if deck space, comfort, and entertaining are top of your list. The Xpress HD17PFC 2011 at 17,0 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.