Most programs will have content for you to use but of course it helps if you can edit the content to make it unique.
I find it is easier to write your own casino content compared to poker content where poker can cover so many areas whereas with casinos you are fairly limited but most people are typically searching for the same thing: bonuses, slots, blackjack, no deposit bonuses, progressive jackpots, etc... Casino and game reviews tend to do well and all you need to do is try the casino for free, play the games, take a few screenshots and you can simply write about your experience. I have game reviews, casino reviews, slots data and all the screenshots for thisisvegas (Rival) if anybody wants them
John