When two boats share the same hull type — in this case both the Larson LX 710 I/O 2012 and the Larson LX 850 I/O 2012 are modified vee designs with composite 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 — Larson LX 710 I/O 2012 at 17,1 ft versus Larson LX 850 I/O 2012 at 18,4 ft. At 204 lbs and 245 lbs respectively, both sit in a similar weight class — either should pair comfortably with most mid-size SUVs and half-ton trucks, though always confirm your specific tow rating with the motor added.
Both boats share a closely matched power ceiling — 135 hp for the Larson LX 710 I/O 2012 and 135 hp for the Larson LX 850 I/O 2012. 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 carry nearly identical fuel loads — 19 gal and 19 gal — so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Larson LX 850 I/O 2012 is rated for 8 passengers, while the Larson LX 710 I/O 2012 caps at 7. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Larson LX 850 I/O 2012 could be the deciding factor.
Bottom line: Choose the Larson LX 850 I/O 2012 if your priority is putting more people on the water — it handles 8 passengers and at 18,4 ft it has the deck room to back that rating up comfortably. The Larson LX 710 I/O 2012 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 7 that costs less to run day-to-day.