Much of this is dependent on your goals for Steem. If you are someone who is going to be using the platform for a long time, or indefinitely, I would strongly advise powering up with the 30 Steem, because by increasing your stake, you increase your vote value, which in turn, increases curation rewards. To me, it's the logical thing to do.
That isn't to say that maybe you couldn't keep a little on the side for day trading, or pulling out. Really, it's entirely up to you!
I hope this answer helps!