That depends entirely on your specific use case. Prime lenses can be harder to use because what's in the frame is dictated by the lens' distance to the intended subject. You cannot zoom in or out from a stationary position; your body has to be the zoom mechanism for correct framing. Telephoto primes can also be prohibitively expensive, but with that expense comes the pinnacle of lens performance.  Telephoto zooms have a range of focal lengths, allowing you to alter compositions on the fly. The range of focal lengths means you can save weight and space in your camera bag and alleviate your budget at the expense of some reduced sharpness and light gathering.