The Weld-Craft Duck 2013 is a modified-V design and the Weld-Craft RL 52 (16 ft.) 2008 is a flat-bottom 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.
Both boats share a closely matched power ceiling - 25 hp for the Weld-Craft Duck 2013 and 35 hp for the Weld-Craft RL 52 (16 ft.) 2008. Real-world performance will come down more to which motor is actually bolted on, its load at the time, and whether it's a 4-stroke or 2-stroke setup.
Both boats are rated for 4 passengers - a good fit for a family of four or five plus guests. Comfort at capacity is another matter; the longer hull typically means more seat options and better weight distribution.
Bottom line: The Weld-Craft Duck 2013 and Weld-Craft RL 52 (16 ft.) 2008 are closely matched on the specs that matter most. Test-ride both on the water you actually use, check current dealer pricing, and factor in long-term service access before you sign.