When two boats share the same hull type — in this case both the Tiara Yachts 3900 Open 2009 and the Tiara Yachts 5800 Sovran 2008 are modified 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 Tiara Yachts 5800 Sovran 2008 measures 57,0 feet overall (2008), giving it roughly 18,0 additional feet of deck space compared to the Tiara Yachts 3900 Open 2009 at 39,0 feet (2009). Weight tells a clearer story for trailering families: the Tiara Yachts 5800 Sovran 2008 tips the scales at 435 lbs — 190 lbs less than the Tiara Yachts 3900 Open 2009 at 245 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 600 hp, the Tiara Yachts 3900 Open 2009 has a 165-hp advantage over the Tiara Yachts 5800 Sovran 2008's 435-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Tiara Yachts 3900 Open 2009 carries 535 gallons versus 65 gallons in the Tiara Yachts 5800 Sovran 2008. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.

The Tiara Yachts 3900 Open 2009 is rated for up to 12 people. Passenger data for the Tiara Yachts 5800 Sovran 2008 wasn't available.