I'm the other way around - I won't say 'never' but it is extremely rare that I can acheive a vaginal orgasm with just a toy and no clit stimulation, whereas I cum quite easily when my man fucks me.

I've never used a Sybian, though I'd like to , and understand they are quite different. The Rabbit doesn't quite fit your question because it does clit stim and vaginal (and anal, depending on the model) at the same time.