Palmer, I'm not aware of any bugs you should be particularly concerned about in the sneaky peek builds; that isn't a guarantee that none exist, of course. For what it's worth, I'm trusting my OmniFocus database to the sneaky peek builds, and I haven't had any problems yet.
With the 1.8 release, we're trying to continue our efforts to streamline OmniFocus' workflow and make it easier for new folks to learn the application. If you'd like to be part of that discussion, it may be worth installing the sneaky peek builds, but if you just want to get on your work, there's no real downside to sticking with the current release.
For more information on the workflow changes we're discussing, check
this thread. That should give you enough information to make a decision as to whether 1.8 makes sense in your workflow. Hope this helps!