Hi, thanks for your comment. The sentiment analysis algorithms are being constantly fine tuned using new data sets. There are some inaccuracies but as the results are averaged out using large quantities of text, the inaccuracies do not influence the overall sentiment significantly.
-I connect to my wifi using a really good asus router. Sentiment 9.0
-I often lose connection in locations where previously I had excellent reception. Sentiment 8.0
-it worked great until july this year when it stopped receiving a network signal. Sentiment 7.5
-the samsung exclusive touchwhiz apps were gimmicky at best. Sentiment 9.0
Etc. If it's unbiased I'd guess the errors would average out, though.