When two boats share the same hull type — in this case both the Zodiac Medline II 2008 and the Zodiac Pro 550 2010 are inflatable rigid designs with rigid inflatable 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?

On paper these two are close siblings in the size department — Zodiac Medline II 2008 at 19,0 ft versus Zodiac Pro 550 2010 at 17,2 ft. Weight tells a clearer story for trailering families: the Zodiac Medline II 2008 tips the scales at 1 432 lbs — 737 lbs more than the Zodiac Pro 550 2010 at 695 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 Zodiac Medline II 2008 has a 60-hp advantage over the Zodiac Pro 550 2010's 90-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 Zodiac Pro 550 2010 is rated for 12 passengers, while the Zodiac Medline II 2008 caps at 5. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Zodiac Pro 550 2010 could be the deciding factor.