I have been to both many times. I love the Universal in Hollywood with the outstanding, long tram ride (definitely takes you behind the scenes) and everything, but honestly, there is no comparison. There is so much more to do at the Universal in Orlando. Remember, there are two parks, instead of just one, so you get almost everything the Universal Hollywood park has, except for Backdraft, plus many, many more incredible attractions. I also think the Citywalk in Orlando has a slight edge to the one in California. There are no true "on site" hotels in California. They are owned by Sheraton and Hilton and do not have the agreement Loews (the resorts at Orlando) has for the Front of the Line Access. That, in and of itself, makes it superior to the Universal in Hollywood. All that being said, I would jump at the chance to go to either one. (traffic and location is more nerve wracking in California.) Any other questions, please feel free to ask.
I just saw where you said you are going to California anyway and should you try it. Definitely!!! Just know it's not quite as incredible as the one in Orlando.