Unless Powell is not 100% healthy for some reason, I think he is clearly the better player now, and would have been considered the better player coming out of high school too - although I don't think that matters. But, Powell might not end up being the better player in the long run.
Most importantly, however, I don't think taking one should have anything to do with the other. Podziemsky shouldn't play major minutes next season. He's a long-term core guy with the potential to be a really good college player (and play professionally too with his size). Powell, on the other hand, would play major minutes next season if he comes to UK (and would probably start at 2G, with Allen at his natural SF position).