Can't speak about that particular ship, but NCL was great! We too had our doubts after reading mostly negative comments about Norwegian in general when we booked our first cruise. We decided to take our chances and had an awesome time!
Keep in mind that thousands of people sail these ships each year, yet only a handful write reviews. People tend to write more about their negative experiences, rather than the good ones. Plus, if you notice, sometimes the same people post reviews on several message boards, so the quantity of bad reviews might not be as high as you think.
The best thing you can do is to go with an open mind and try to enjoy yourself. There will always be something that isn't how you expected it to be, but that doesn't have to ruin your cruise.
Relax and have a good time!