It's true that with a fixed gear/ss you can't always have the appropriate gear for any situation, but it's relatively easy to find a ratio that will work consistently if you are a strong rider. FG drivetrains are more efficient than geared bikes so it isn't quite the same as just leaving your bike in one gear and never shifting. You'd be surprised to learn how not having the option to shift really frees up your mind. Also, I don't see how running a front brake defeats the purpose of a FG in any way.