You better take this.
This means, "You had better take this." In English, we use contractions. When we say, "You had," we simply say, "You'd." However, the way the "d" in "you'd" sounds when said against the "b" in "better," makes it almost inaudible. As a result, many English speakers end up saying and even writing, "You better."
What it actually means is: "You ought to take this," or, "It would behoove you to take this."
You take this.
This isn't something people would generally say as a sentence. We don't say "you" beforehand. When using the imperative voice, we simply say, "Take this." Occasionally, people will add an enunciated "you" before the imperative of a verb, but it's not standard fare. It's only done to make some kind of special emphasis.
It would be said like this in the present indicative. In the present indicative, though, it wouldn't be telling someone to take it.