Node enforces a programming model that puts you down the path to extreme vertical scalability, you know, actually using all the hardware you are paying for. CPUs and the kernels that manage them are good at running code. They suck at waiting for things to happen.

Out of the box the callback model can be difficult to wrap your head around. But if you are serious about writing a vertically scalable IO-bound service, it is currently the only option. There are some add-ons to make the code less ugly, but you still have to have the mental model down.

It's a lot like multi-threaded programming, or functional programming. It's a matter being able to visualize the flow and pass context around. This takes time to change the way you think.

If you approach problems in Node like you'd approach a problem in a functional language the spaghetti of callbacks becomes much less of a burden.

For the async haters out there operating at scale. How many of you have farms of machines with idle CPU's, maxed out memory, and practically idle network interfaces? Yeah, I thought so.