It is a good movie but with many reasons that it may be a hit.
 Long period: The most important one is the 2 months of gap before the release of NEWYORK. People were desperately waiting for something to come out and it is luckily NEWYORK from YRF. People just couldn't control and gone to watch.
 Star cast: John, Katrina and Neil are enough to get the people in. Get rid of these 3 names and count on the people who are going to watch it?
 A name and promos: NEWYORK (people living here and dreaming about USA, will surely go for it) and the promos are made in a way that the movie has lots of "happening" things in it.
I personally feel that the movie has been made for the critics (and not for the common men who want "masala" in hindi entertainer). This movie has been made to grab some awards and to work in overseas more than in India.
Performances are good but on the other hand the story is.
While watching a movie, i reminded about another movie which was released few years ago - AUZAAR (Salman Khan, Shipla Shetty, Sanjay Kapoor) which had the same story. A hero, another hero and a heroine studying together in a college, both the heroes falling in love with a same girl, 1 of them is getting married to her and dealing with mafia-business, hero is a cop and helping friend to come out of the situation.
The same story, theme and a plot applies here but in a HUGE way. The most benefit to this movie is that it came out from YRF.
That's all about NEWYORK.