As predicted, Apple has abandoned their button-free iPod Shuffle design for a return to the "ring button" layout of the very popular clip-style iPod Shuffle. It's a much better design.
Overall, it's still expensive and feature-poor compared to the Sansa Clip, which offers more memory, an FM tuner, and a screen, but it is a much nicer-feeling product. The Sansa Clip still feels like a toy, as do most non-Apple MP3 players.
Ultimately, the new iPod Shuffle is a mature, solid product and in many ways, a perfect design.
The new Nano is a bit more baffling. I suspect it's just marking time and covering a price point for Apple, as they can't yet get iPod Touches down to a cheap enough price point, can't charge more for the Shuffle, and are unwilling to leave a gap in their iPod price line for a competitor to fill.
As a technological achievement I suppose the new Nano is rather nice, but as a product, it's sorta goofy. I did somewhat anticipate their grafting a touchscreen onto such a tiny form factor, but after the addition of the camera to the Nano in the previous round of revisions, I expected it to be the Shuffle that got it, rather than the Nano.
That would have allowed Apple to claim they were still moving forward on the Shuffle design rather than "retreating" to a previous one, and would have left the door open for more advancements in Nano land (the lack of a camera on the new one is arguably a big step backwards).
In its current design, the Nano is designed to be clipped onto one's clothing, like the Shuffle. But in practice, this means both the display and the controls for the unit are facing out and away from the user, so the user has to look down at their clothes and/or pull the Nano towards themselves to see and manipulate it. Because the screen is the control surface, and because it is so tiny, it is very difficult to hold the Nano while controlling it, and while you are pushing its surface, much of the screen is obscured.
Contrast that with the "candy bar" Nano design. Its hardware controls and orientation allowed for "blind" operation - you could skip tracks or pause in your pocket, without looking at the screen. Because it was "candy bar"style and size, it afforded gripping in the hand while looking at the screen, without obstructing the screen.
The new Nanos also don't allow users to install or run apps (and I'm glad about that, because otherwise there would be yet another Apple mobile configuration to design for), but their visual interface design picks up many of the cues of Apple's higher-end products, including fancy animations, a pivoting display, "multi-touch", and more. Much of this is simply gratuitous, but goes a long way to justifying the pricing in consumer's minds.
I find the much-vaunted "multi-touch" control silly and inferior to the simple elegance of the click wheel for something like the Nano. The Nano itself is hard to pin down - it's too fancy and fiddly for the gym, the Shuffle being far superior for that.
Eventually, I expect Apple to merge these two products - their design framing shows they're headed this way. Again, I suspect it's a matter of covering price points while they wait for component and design costs to come down, for all aspects of the product line. When they do, I hope they manage to keep more of the ring button design and less of the touchscreen, but past behavior sadly indicates otherwise.
In the meantime, Apple manages to monetize its quirky design choices and its decisions to emphasize the "feel" of products as much as their actual features.
Most people, even hardcore audiophiles, are better off using a smartphone or iPod Touch-type device as a music player. If you need a portable for the gym, I'd still recommend the Sansa Clip over the Shuffle unless you're an all-Mac person. The Sansa Clip may feel like a toy, but that minimizes the pain you feel when you drop it or lose it.