Both the Spectre 328sc 2010 and the Spectre 38 Crossover 2011 are catamaran 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?
For family outings this is probably the sharpest distinction between the two. The Spectre 38 Crossover 2011 is rated for 16 passengers, while the Spectre 328sc 2010 caps at 5. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Spectre 38 Crossover 2011 could be the deciding factor.
Bottom line: Choose the Spectre 38 Crossover 2011 if your priority is putting more people on the water - it handles 16 passengers and at 38,0 ft it has the deck room to back that rating up comfortably. The Spectre 328sc 2010 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 5 that costs less to run day-to-day.