I have a LevRG and have seen the Cell in action side by side with the LevRG, both are excellent balls, but for true heavier oil, I'd have to go LevRG everytime. It's by far the strongest ball I've ever seen and should win ball of the year IMO. Mine is drilled according to the sheet for high track players with a Sharp Break Point.
Both are balls that everyone should have in their bag, but for the purposes mentioned here I'd have to vote for the LevRG.