I don't think this really takes a lot of thought. You're almost certainly better off playing JV. Last year, my son's team took four sophs up to varsity, but cut him. He was mad, especially since our coach conceded to him that he was better than the senior and junior at his position. The coach told him he was going to play those guys and that was all there was to it. He also told my son that he needed playing time, not varsity bench time. He was so correct about that.
What you should be concerned about is getting as many innings or at-bats as you can get. By the way, two of the sophs that stayed on varsity didn't play very much and really wished they'd have been on JV where they'd have regularly played.