I have bikes with brifters, down tube shifters, and Gevenalles (shifter levers mounted on the front of the brake lever).
I don't presently have a bike with bar end shifters but I have a set of bar end shifters waiting to go on the right bike. I like them fine. My second bike (as a kid) was a Raleigh Gran Sport with bar ends.
My only issue with bar ends is that on some bikes my knees brush the levers, but only when sprinting or climbing raggedly.