It is great to see more crowdsourcing data getting open sourced.
I haven't read the research but I'm assuming he used a fairly unrestricted crowd. I'd be interested to use the crowd to rate sentiment analysis results from this model vs. CrowdFlower's Senti to see how the model fares against a specialized sentiment analysis crowd. I would be very surprised if the model won. I am willing to run a comparison if there is sufficient interest in the data.
I don't know if the "raw" data from MTurk is included in the data set. But at least the finalised data has been released for quite some time now.
http://nlp.stanford.edu/~socherr/stanfordSentimentTreebank.z...
As for the value of the data, I have heard numbers around 10,000 USD. But I have little more than academic gossip to back these numbers up.