If you are doing much impact training, either hitting hard objects or other people's sticks I'd go with the rattan. Rattan reduces the amount of vibrations transmitted back to the hands, plus as Rich points out, it is safer for anyone around you, rattan doesn't shatter, it folds.
If this is for forms work, whatever you find visually appealing.
i like rattan best just because of the weight, natural texture, and it's pretty. oak is nice, but rattan is better all the way around. less risk of injruy via splinters when striking targets.