For me I always used to be the type that would go out extremely hard and hold on, and while that works great for a PR generally, its not the best for racing. For racing I definetely agree with pass once and make if final. I found that I was able to beat two guys who managed to beat me earlier in the xc season when I just lead the whole race and they stuck me by going out more calmly and sharply surging slightly past the half, giving the appearence of boundless energy even if you are dead for the simple intimidation factor. This works conversely with surges by others. I know in the evaluation run for my xc camp an illinois guy surged hugely on me in the 2.4 mile run, and I stuck him even though it hurt, and managed to pass him later on. Think of it like a leash, once you break from that guy in front of you more than a few meters to join back up with him is extremely difficult, and you will probably not see him again in that race.
Mostly though it comes down to your body type. For me, a more strict long distance guy with not much kick to speak of, going hard from a decent ways out, 500m in a mile, 600 in a 2, 800 in a 5k, has helped me to eliminate guys that could beat me in the 100m sprint at the end. Or vice versa, stay with somone till the end if you know you can beat them in the last 100. Just know your body and it's limits, and you'll never go wrong.