In Hunterdon County, Flemington and Clinton both have town centers. Any other towns in Hunterdon with town centers would be too small to notice.Flemington is noted for it's outlet shopping (about 60 stores)
In Somerset County they're are many towns with a large town center. Somerville being the largest town but you also have Bernardsville, Manville, Bound Brook,Warren has sort of a town center with malls at the intersection of Warrenville road and Mountain Ave. Bridgewater does not have a town center but it does have the Bridgewater Commons shopping center which is the largest in Somerset County.
I am sure I have forgotten some and I purposely did not rate any of the towns as being better than any other.
Hunterdon has more open space and farms, Somerset has more homes and more people.