I also think the American pronunciation is clear, especially in pronouncing the R at the end, which is often dropped or softened in Brit/Aus speech. But it also has a lot to do with how well you recognise the pronunciation, not just the clarity.
This vlog includes the Australian presenter explaining how she tried to order water in a New York restaurant... :)
www.youtube.com/watch?v=M3bXh-EY_V0