I has been shot lavishly with a big budget of Rs 180 crores so it definitely is visual treat to watch the movie and Shankar's direction is also good but the weak script of I ruins every other good aspect of the movie.
Watch it only for Vikram otherwise you can skip it.
I, which is basically targeted at the South Indian film industry, will have to depend heavily on the word-of-mouth in order to do good business in Hindi film circuit. A very special mention to the make-up (Sean Foot and Davina Lamont) and also to the team which has done the film's VFX work.
On the whole, go for I only if you are a big fan of extravagant masala films.