I know students who have graduated from these 2 schools, and they all had outstanding experiences. I think these 2 are more alike than different. Whitman would be much better known were it not in Walla Walla. It has a “can’t get there from here” location, even more so than Grinnell. The graduates of Whitman I’ve known all ended up in either Seattle or Portland, despite being from Minnesota. The grads I’ve known from Grinnell mainly ended up in Minneapolis.
This is one where I feels it’s safe to choose based on vibe. Best wishes!