Since they limited the influence of the community, I think Steem-bounty is an excellent tool to host contests. Mostly because every one who gives a valid answer is a winner and gets a prize. You, as a host, can decide which answer is more valuable than another and deserves a bigger reward.

On top of that, the payout is done on autopilot, so there is no risk tat you forget to payout the rewards (and you don't have to write a fairly useless winners announcement post.)