Both the Crest II LE 18 2007 and the Crest III Classic 20 2008 are pontoon 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?
On paper these two are close siblings in the size department - Crest II LE 18 2007 at 18,0 ft versus Crest III Classic 20 2008 at 20,0 ft. Weight tells a clearer story for trailering families: the Crest III Classic 20 2008 tips the scales at 2 515 lbs - 365 lbs less than the Crest II LE 18 2007 at 2 150 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 115 hp, the Crest III Classic 20 2008 has a 40-hp advantage over the Crest II LE 18 2007's 75-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load.
For family outings this is probably the sharpest distinction between the two. The Crest III Classic 20 2008 is rated for 13 passengers, while the Crest II LE 18 2007 caps at 10. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Crest III Classic 20 2008 could be the deciding factor.
Bottom line: Choose the Crest III Classic 20 2008 if your priority is putting more people on the water - it handles 13 passengers and at 20,0 ft it has the deck room to back that rating up comfortably. The Crest II LE 18 2007 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 10 that costs less to run day-to-day.