I just wanted to quickly point out that Hazel will not be in the Mac App Store. The main reason is that Apple is only allowing app bundles to be submitted. Since Hazel is a preference pane, it is categorically disallowed. Also, the restrictions disallow certain key features currently in Hazel as well as new features to be included in 3.0.
Even without these policy restrictions, there are issues of how demos and upgrades are dealt with. I prefer that my customers buy my product with the knowledge that it suits their needs and there's no better way to do that than to have an easy way to demo the product and convert that demo to a full product. Also, the MAS lacks any way to handle paid upgrades and with Hazel 3.0 on the horizon, I need issues like this worked out.
If Apple relaxes their restrictions, I may consider the MAS but keep in mind I would only participate in such a manner that it doesn't punish my current customers.
That all said, Hazel will always be available for purchase directly from me. While many consider having to deal with the customer as a burden and welcome having Apple as a middleman, I prefer to have a direct relationship with my customers. So, even if Hazel is ever made available on the MAS, I will still support and prefer direct sales via this site.
Please spread the word about Hazel and educate users that there's more to the Mac app universe than the App Store.