Yeah, I would say you're right. Buijs probably has more variety in attack when she is on form but to me Zhang has the advantage because of her accuracy and reliability.
I don't like Zhang. She's not that solid on reception, to be considered an all-around OH like Logan, Picci etc.. She receives decent most of the time.. attacking is her forte, although her approach is weird, she looks heavy to me (not overweight by any means, just heavy jumper) She has a very good serve