It depends on the usage. If you're going for speed runs - sensorless would be better. If you're bashing, sensorless would probably also be better, as it is more resiliant than sensored (no sensor leads to come loose, or get water in).
However, if racing, sensored is simply better for the low end control, though the best systems are the 'dual drive' systems, where they start sensored, then go sensorless for the extra efficiency and speed.
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