I have a pretty "agile" approach to updating the beta release. Mostly you won't realize it unless you check the News page too regularly, but I upload new patches to WazHack far more often than just the larger announced beta versions. Since the first beta release on March 13, there have been over 200 patch releases to the site. Often these just contain bug fixes which you'll hardly notice, but sometimes I push out a little feature or two. Since beta5, patches have gone up adding keyboard configurability and improving the way pets keep and use their inventory (they'll no longer randomly pick up and drop stuff either). Sometimes a little bug finds its way in with these features (eg. key config broke controlled teleport - thanks Kyo), but the same is true for bug fixes (an urgent fix to dog ladder handling broke lots of other monsters, but was quickly fixed).
I'll never take it for granted, but I really appreciate the sometimes near instant bug report I get when I make a mistake!