I have played with it and I love some of the concepts. For instance, the collection functionality is just fandamntastic. Automagic collection of my digital stuff? Absolutely! I'm there! The way things are broken up (Collection, Processing, etc.) is really helpful. Small touches like the different colored sidebar backgrounds depending on the current mode make it a very enjoyable app. That being said, I'm not sure I like that it looks like the "If they mated" of GarageBand and Mail; however, it's still the best-looking GTD app out there (OmniFocus, the bar is set high.) and just because it doesn't match my personal taste doesn't mean it isn't a good looking (lickable?) app. (I also think it could have been intended to be a cross between Delicious Library and Mail, in which case there isn't as much incongruity between the UI and the app's function.)

Alas, it is still feature incomplete and unreliable in some areas. (For instance, I just tried to create a new topic for the reference section and it created a new context but put it under Reference. Apparently no way around it.) I would like to see more integration with the iApps (iCal and Address Book in particular). It would also be nice if it could interact with Salling Clicker to track my phone calls, especially missed ones. Then, in the processing phase, I could decide if I should call the person back. I am also not sure I can totally embrace the "reference" system as it isn't anywhere near as powerful as DEVONthink.

My conclusion after spending a little bit of time with it is that Midnight Inbox is an app that has been extremely well thought out and has a ton of potential to improve. But for me, the $35 price tag combined with the list of "known issues" is a bit too much for me to integrate Inbox as a significant part of my trusted system.