Basically, the higher the printer's DPI output capabilities, the better the final print is going to look, no matter what the resolution of the original file was.
Don't be fooled by anyone who would tell you that the benefits of higher resolutions are a myth -- they're just trying to cover for their own hardware's inadequacies! More resolution means richer, more vibrant prints with deeper colors and sharper lines and edges.
Let's just put it this way: why would every single printer made today use 1440 dpi if it *wasn't* the way to go? Modern materials are designed to maximize the benefits of higher dpi counts to produce superior prints. Period.