I tried Hulu on my Roku. It had more TV shows while Netflix had more movies. When i had to choose one to pay for, I chose Netflix. I didn't have any trouble canceling my Hulu account, so give it a try and see how you like it.
Netflix offers a 3 month trial I think don't quote me on that... I have tried both on the vtab and they work pretty darn well.. Really cool if you ask me. But I think they both require a credit or debit card