Bitterness, mostly.
Earlier, I’ve praised Disco. I like the app, I like the interface, I like the effects and I like what it does for you. Complaining that you can do a lot of it in Disk Utility is missing the point of the app.
As much as I’ve liked Disco the app, however, I’ve been skeptical about the attitude of its creators. “Don’t like me, bite me” isn’t a good attitude to hold towards people. John Casasanta and his fellows had an excellent opportunity to turn their ship around - saying “you know what - let’s zap our PRAM and start over, because this isn’t really benefitting anyone”. Instead, they’re building a wall, solidifying the ‘you’ vs ‘us’ and marketing purposefully to one subset of people at the explicit cost of another. Who does most people sympathize with in those Get a Mac/Mac and PC ads? (Hint: he’s written a book.)
You might say “well, this is just marketing for you”, and you’d probably be right. I’m still worried that this would help put more rifts through the development community. We already have the mindless Carbon vs Cocoa and Mac OS 9-posse vs NextStep-posse divides.
What people will eventually buy is software that works and looks and feels good. This is John Casasanta-and-Co’s stated goal, and with that I agree, but it’s also something everyone else with aspirations for a good UI is working towards, and something that’ll become a lot easier very shortly. For any part in this conflict to claim victory or superiority is bad for everyone.