Both means have clear advantages and disadvantages. However. New thought. Why not use both??
There are a few marketing campaigns out there that are trailing the use of both. It will be interesting to see the results of which method gets used the most.
Having both methods available caters to a wider audience, since NFC capable devices are limited at this point in time.
Here is an example of a tag with NFC and a QR code built in. It is also a good comparison of the usabilty of each technologies so take a look at this:
Here is a poster trail of both the technologies. Hopefully they post the results!