There are quite a few different bar end mount mirrors out there for drop bars. Mine was an inexpensive Bell brand mirror I found at Walmart. I like it, but have to consciously make myself look down to use it. I'd make sure you can adjust the angle appropriately. I was riding my other bike today that doesn't have a mirrors and I noticed its absence. I do use it.
Those mirrors that come up out of the brake hoods look interesting. I'm not sure how well they work.