Will an dual sport be a good daily commuter?

I am getting a motorcycle to drive back and forth to work, it is a 14 mile drive in one direction. I do live on a dirt roads (about 1/4 mile). Would a dual sport be better than a street bike?Since it is basically a dirt bike,do the handle pretty good on the road? Will it wear out faster since I do more paved road driving than dirt?This will be my first motorcycle and all the bikers are telling me to get an at least 500cc because I will outgrow the smaller bike or it will not be fast enough for commuting to work?