Both the Starcraft Marine Fishmaster 210 2012 and the Starcraft Marine STX 206 Viper 2011 are modified-V designs, both built in aluminium, 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 - Starcraft Marine Fishmaster 210 2012 at 20,8 ft versus Starcraft Marine STX 206 Viper 2011 at 20,5 ft. At 1 535 lbs and 1 535 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 - 250 hp for the Starcraft Marine Fishmaster 210 2012 and 250 hp for the Starcraft Marine STX 206 Viper 2011. 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 - 52 gal and 50 gal - so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Starcraft Marine Fishmaster 210 2012 is rated for 10 passengers, while the Starcraft Marine STX 206 Viper 2011 caps at 6. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Starcraft Marine Fishmaster 210 2012 could be the deciding factor.
Bottom line: Choose the Starcraft Marine Fishmaster 210 2012 if your priority is putting more people on the water - it handles 10 passengers and at 20,8 ft it has the deck room to back that rating up comfortably. The Starcraft Marine STX 206 Viper 2011 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 6 that costs less to run day-to-day.