Both places are considered an excellent choice of community for families and some choose one over the other based on proximity to work and the time it takes to get there, considering specific routes and traffic patterns. Many buyers, however, who are likely to consider Lexington would also consider Wellesley and choose one or the other based on an individual property (its size, price, privacy, etc.) rather than town.
Lexington - more central in terms of access to Route 95/Route 93/Route 3 and 2 to Cambridge and to Boston there on.
I live in Lexington - so maybe I have that bias.
Wellesley - Route 9 I have felt has traffic lights and bottle necks for commute.
Town amenities - (personal)
Proximity to Boston
Hope that helps!
Everything on the market in Wellesley:
Everything on the market in Lexington:
Massachusetts Premier Buyer Brokerage
Some will choose one and some the other.
Ask the chambers of commerce that question and see what they say are the real differences.
Wellesley has more of a college presence than Lexington, w/o a doubt.
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Love to show you around both communities as well as some of Boston other excellent ones based on your needs, Newton, Dover, Needham, Brookline, Weston