When two boats share the same hull type — in this case both the Zodiac Medline IV 2011 and the Zodiac N-ZO 690 2011 are deep vee designs with fiberglass construction — 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 Zodiac Medline IV 2011 measures 27,9 feet overall (2011), giving it roughly 5,0 additional feet of deck space compared to the Zodiac N-ZO 690 2011 at 22,9 feet (2011). Weight tells a clearer story for trailering families: the Zodiac Medline IV 2011 tips the scales at 3 527 lbs — 3 194 lbs more than the Zodiac N-ZO 690 2011 at 333 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 350 hp, the Zodiac Medline IV 2011 has a 100-hp advantage over the Zodiac N-ZO 690 2011's 250-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Both carry nearly identical fuel loads — 106 gal and 106 gal — so range won't be a tiebreaker here.

For family outings this is probably the sharpest distinction between the two. The Zodiac Medline IV 2011 is rated for 8 passengers, while the Zodiac N-ZO 690 2011 caps at 5. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Zodiac Medline IV 2011 could be the deciding factor.