For years, the standard for cranberry juice in the U.S. has been Ocean Spray Cranberry Juice. Ocean Spray has been making cranberry juice since 1930 and uses a cooperative of over a thousand cranberry growers.
Back in my college years in an effort to save money, I used the cheaper store brands. I thought I was getting the same thing, but upon switching back to Ocean Spray Cranberry Juice, I could tell that I had missed out.
The bargain brands were bland and lacked the snappy tartness that cranberry juice should have. Since most cranberry "juice" usually has less than 50% actual cranberry juice and added sugar and water, the bargain brands can easily cut way back on the amount of actual cranberry juice.
Ocean Spray gives you a sufficient amount of the real juice to provide the appropriate tartness and snap that you want in cranberry juice.
You may be thinking, why not just use 100% cranberry juice? Well, real cranberry juice is very tart - too tart for most drink recipes. So you want some sweetener to counteract the tartness of the cranberries, but not too much. As is often the case, you want to strike a balance. If you really want to use 100% cranberry juice for health reasons or other reasons, increase the amount of sweetener in the drink recipe to compensate.
And by all means DO NOT substitute Cran-Apple, Cran-Grape, Cran-Raspberry, or Cran-Anything for cranberry juice in a recipe. I did this once on a ski trip (the girls got Cran-Apple by mistake) and it made a hellish vodka and cranberry juice.