I'm really interested to hear what happens with this issue too. With all the R&D effort Microsoft claims to have put into reducing lag and increasing accuracy, and for them to actively push that feature in their release presentation, I struggle to comprehend how it could then be bad enough that I've heard people claiming 'note taking is unusable because of lag'.
I'm hoping it's 'just' hover lag and the initial activation force that people are noticing and I'll be able to get used to it (SP3 on order) but if it's actually an issue then I'll be hugely disappointed.