Update
There is a bug in the addon that allows us to issue fine-grained control over permissions (what you can and can't do), and when it crashes, it prohibits you from placing or destroying blocks. I think I have configured the server to reconnect to the database on timeout, but there's only one way to find out.
Update
The Goon Minecraft server has now been updated to 1.6.6. You can view the changelog here.
CPU use seems to have increased slightly over the 1.5.x branch, so I'll be keeping a close eye on it. If it spikes too much, I may have to revert it to 1.5. As it stands, things are looking OK and a revert seems unlikely.
You should also have access to trap doors and numerous other features including, but not necessarily limited to, the Nether. The Nether most certainly works but watch out for ghasts. Their fireballs will explode and destroy a certain number of bricks near its impact site.
Also, Permissions 3.x has changed the underlying structure somewhat, so I've migrated its settings over to an SQL backend. This means that I had to recreate the permissions groups by hand. If you're having trouble doing something on the server (specifically, building or destroying blocks), contact me either through here or on the server (if I'm on), and let me know. Most everyone should be either in the users group or the moderators group, and your permissions should be mostly analogous to what they were before. As always, users new to the server will be unable to destroy blocks or build anything until they receive permission to do so. If you feel something isn't right, please post here along with a description of the problem and the approximate time of day that you were on.
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I may be updating the 'goon server to 1.6.6 sometime this evening. There are a few minor issues I have encountered with configuring Permissions and a couple of other plugins (WorldGuard/MyHome/etc). I think I have it ironed out on my test server; when I do, I'll be copying the appropriate configs over to here.
This post will be updated whenever I get to adding 1.6.
Also, note that 1.6 adds a few new features (and breaks others). Specifically, trapdoors have now been added to the game.