1. Answer: It depends on everyone's taste and these rankings change all the time. According to RankMyPorn, at the moment, the top ranked Under 30 Male Pornstars in the world are: Alex Legend, Bruce Venture, Chad White, Chris Diamond, Damon Dice, Seth Gamble, Johnny Sins, Alex Jones, Troy Francisco, Ramon Nomar, but these will change based on what people vote.
2. Answer: It changes. You can see the latest rankings on RankMyPorn.com and also vote on it for free.