Bump and normal essentially are identical in terms of the outcome.

Bump is adjustable, normal is not. If you think being forced to adjust bump strength is a pain in the arse, then normal is better. If you think being not allowed to adjust bump strength is a pain in the arse, then bump is better.

Normal is a tiny bit faster than bump. On my machine, rendering around 500 thousand pixels of some surface, the normal mapped one will be 1 second less render time.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)