Both the Tahoe Boats Q7 SSi 2009 and the Tahoe Boats Q8i 2010 are modified-V designs, both built in fibreglass, so 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 - Tahoe Boats Q7 SSi 2009 at 20,0 ft versus Tahoe Boats Q8i 2010 at 21,0 ft. Weight tells a clearer story for trailering families: the Tahoe Boats Q8i 2010 tips the scales at 3 500 lbs - 469 lbs less than the Tahoe Boats Q7 SSi 2009 at 3 031 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.
Both boats share a closely matched power ceiling - 300 hp for the Tahoe Boats Q7 SSi 2009 and 320 hp for the Tahoe Boats Q8i 2010. 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. Fuel capacity breaks the other way: the Tahoe Boats Q8i 2010 carries 54 gallons versus 45 gallons in the Tahoe Boats Q7 SSi 2009. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
For family outings this is probably the sharpest distinction between the two. The Tahoe Boats Q8i 2010 is rated for 10 passengers, while the Tahoe Boats Q7 SSi 2009 caps at 9. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Tahoe Boats Q8i 2010 could be the deciding factor.
Bottom line: Choose the Tahoe Boats Q8i 2010 if your priority is putting more people on the water - it handles 10 passengers and at 21,0 ft it has the deck room to back that rating up comfortably. The Tahoe Boats Q7 SSi 2009 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 9 that costs less to run day-to-day.