Rene Richie has some great insights on Apple Watch.

First the problem with ‘day-of’ reaction pieces:

Demo areas aren’t real life. The product you’re experiencing isn’t yours. It isn’t connected to your accounts, it doesn’t have your data, and it isn’t set up to your personal tastes. You’re also surrounded by people and noise, you have limited time, and you want to try out as many features as you can. It’s tough to keep the context in mind, to set your expectations accordingly, and to try and extrapolate a product’s demo to its real-life usage. It’s what leads to day-of reaction stories that are sometimes very different to week-in review pieces to months-in review pieces.

And on how Apple Watch fits into the hierarchy of devices (Mac > iPhone > Watch): Notifications and, to some extent Siri, not icons, are going to be the primary portal to apps and activities.

If deeper, longer-form interaction is needed, you’ll absolutely still be able to do it. You’ll be able to tap and spin and swipe and otherwise move through glances and apps and do almost anything you want to do. You’ll even be able to use handoff to continue an especially deep or time-consuming activity on your iPhone, the same way you can handoff from your iPhone to your Mac today.

That’s the advantage of Apple staging convenience and complexity. You can do more with an iPhone than ever before, but you still can’t do everything you can do on Mac, and some things you certainly can’t do as efficiently. You can do a lot of very important things, however, and do them even more conveniently. And that means you don’t have to go running back to your Mac as much as once did.

With the Apple Watch you’ll also be able to do a lot, but not everything you can do with the iPhone. You’ll be able to do some very important things, however, and even some unique things, even more conveniently. And that’ll mean you won’t have to go reaching for your iPhone as much as you do now.

The iPhone is a finer-grained convenience than the Mac/MacBook (for certain things) and the Watch is a finer-grained convenience than the iPhone (for certain things).