I don't think a couple of games are going to change too many peoples advice. Myers is a better prospect. He's one of the top young SP prospects in the majors. Webb is probably pitching better right now, and will probably continue to deliver. He did just have some arm troubles, so that is something to keep an eye on. The D-Backs also have a ton of injury issues to deal with.
It's pretty amazing what Webb has done in his situation, and I'm very happy to have grabbed him. Myers remains the better prospect with a more stable environment to produce W's when his pitching comes around.
In the end, you have to decide what is best for you. If you want the guy pitching better but may be an injury risk grab Webb. He will help you now. If you can afford to wait and hope for Myers to produce like he is expected and get a bigger payoff later, stand pat.
* Steroid induced record