The Xpress HD18 2011 is a flat-bottom design and the Xpress V-Jon FL 2009 is a modified-V design, so you're likely deciding between two noticeably different on-water experiences. Hull type shapes everything from ride quality and fuel burn to dock handling and resale trajectory.
The Xpress V-Jon FL 2009 tops out at 50 hp. Engine specs for the Xpress HD18 2011 aren't listed - confirm with a dealer before selecting an outboard.
For family outings this is probably the sharpest distinction between the two. The Xpress HD18 2011 is rated for 5 passengers, while the Xpress V-Jon FL 2009 caps at 4. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Xpress HD18 2011 could be the deciding factor.
Bottom line: Choose the Xpress HD18 2011 if your priority is putting more people on the water - it handles 5 passengers and at 18,0 ft it has the deck room to back that rating up comfortably. The Xpress V-Jon FL 2009 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 4 that costs less to run day-to-day.