I always thought they were pretty much the same, but the aroma of some gives the impression that they are actually sweeter. The red ones may be white, orange or even pinkish inside. I believe the amount of beta carotene causes this. I even had a variegated one (even the 'fingers' were variegated), but it tasted pretty much the same. The biggest difference I noted was the texture - some were quite creamy, and by comparison the typical store-bought ones appear almost 'mealy' and dry.
Here is a variegated one.