When two boats share the same hull type — in this case both the Zodiac Mark I ST 2009 and the Zodiac Zoom 340 S 2008 are inflatable non rigid designs with 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?
Both boats share a closely matched power ceiling — 25 hp for the Zodiac Mark I ST 2009 and 10 hp for the Zodiac Zoom 340 S 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 5 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 Zodiac Mark I ST 2009 and Zodiac Zoom 340 S 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.