I don't know the weight of the Nacra 17 but if I was making a choice and they were the only two to consider I'd go for the Taipan. They are a great boat.
The best thing you can do is take both for a sail. Even if you disagree with me the answer to the question, for you, should be very clear after trying both of them. Anyhow, it is just sensible to try before you buy.

Good luck,
Regards,
Phill

I know that the voices in my head aint real,
but they have some pretty good ideas.
There is no such thing as a quick fix and I've never had free lunch!