Depends. If the desire it that she gets trained to run medicine as a profit making business and make big bucks the US medical schools lead the pack. If the goal is that she gets trained to practice medicine to benefit patients with a much lesser emphasis, and expectation, of making large profits, then schools in the UK would be the better choice.

It also has to be pointed out that most US medical schools are set up to to operate on student loans that that are set up to be repaid upon completion of residency. Most newly minted doctors start with several hundred thousand dollars in debt. Debt that can be used to excuse higher prices.

The schools in the UK, as I understand it, leave the new doctors far less burdened, and far less concerned with financial issues.