The previous reviewer basically articulated all of my thoughts about Roma word for word. I must give him more credit though.
Taking both of the classes that he offers to his undergraduates, I can assure you that Roma certainly embodies the term "cult of personality" more than any other professor I have encountered throughout my time year (I have another year left, but I doubt I'll meet any professor that matches up to Roma's charisma). However, while I must say that, yes--my photography has improved after taking both of his courses, I do wonder how much I (and others who listen to his every word with the assumption that they are words of wisdom) could have improved even more if such a large part of my time in those classes was not spent on listening to his musings like a disciple. Especially with his Photo 3 seminar--which is handled much more leniently than Photo 1--where much of the class is spent on chatting with Roma and there is much less pressure to produce work consistently. As a result, I found myself scrambling at the last minute to put together the final project for that class. If you really want to improve your photography, definitely reach out to Roma with specific questions and he will answer them, as well as the TA's. The TA's provide the helpful/technical counterpart to Roma's philosophical take on the classes. But of course, Roma is not a world-class photographer for nothing, he is of great assistance if you badger him in your office (which he loves!). Don't be fooled by his intimidating and bully-ish aura (though you inevitably will be at first), he is honestly a very kind and dedicated person who is ready to sit with you in his office for hours and feed you yummy cannolis during the seminar.
If you're gonna take Photo I, definitely try to take it with Roma, simply for the fact that it will be a standout class in your Columbia experience, regardless of how much you end up liking/not liking it. Be prepared to seek out for help on your photography skills and don't fall face first into the trap of Roma's charm. Definitely listen to what he has to say but don't assume that everything he speaks is passed down through God. Like the previous reviewer said, he gets away with a lot more than other people do.
P.S. Don't be afraid to disagree with Roma on something he says! He is (somewhat) open to engaging debates.