Both are excellent schools – congratulations!
I think the biggest, obvious difference is whether you prefer a women’s college or not.
By reputation, Carleton is going to have serious but probably less politically-oriented students compared to Smith. Not sure which appeals to you more.
Also, MN is going to be on average a bit colder than MA. (This was important to my D who ended up choosing Davidson over Carleton b/c of the weather and they gave her a little more aid!)
Good luck and let us know!