Seriously guys, Sonarr is soooo much better.
Runs better, Looks better, management is better, more options, easier to use. It even talks to SABnzbd so you can see download progress and even failures.
You can't even select an nzb to grab with sickbeard if it fails, what shíte is that? Sonarr allows you to custom select another nzb right in the interface.
It has also been grabbing the best quality nzbs and it's phenomenal. (I have ratings displayed in my SAB, integrated from OZnzb indexer - almost everything is rated 4 or 5 stars.)
(You even get a slider for the allowed sizes for SD/HD/BR/etc)
With sickbeard you never know what nzb it grabs and you just kinda hope for the best.... and if it fails you're screwed.
Give it a try!