My store has had the iPods for about two weeks now. I've had occasion to play with them as Flow and Plano.
The thing I like most is that, right now, running the older PDAs and iPods in parallel, we actually have sufficient devices for our team members.
In general, I like the new iPods. There are a lot of corners I don't poke around in much, but I've found the new toys mostly useful. The big drawback, as many have mentioned, is that they don't do backroom functions yet.
On the plus side, the interface is pretty useful. Again, others have mentioned it, but the iPods tend to give you *much* better visibility on all related information you'd like to see.
You have to log into them using your Workbench credentials. Alphanumeric input is kind of a pain, but if you're reasonably active on the device throughout your shift, you should probably only have to log in once at the start. But you may have to provide an unlock code multiple times throughout your shift, which is a little painful.
Even if you haven't been idle long enough to need to give the code to unlock the device, it still feels a little slow under sporadic use. Draw the device, hit the home button, wait a second for the screen to wake up, swipe to unlock, wait a couple seconds for myWork to come into focus, wait another five seconds for the optics on the sled to wake up so you can scan. I don't know iOS or the sled interface enough to know whether there's anything that can be done about this, but it would be great if they could shave off some of that down time. It's certainly not the end of the world, but it's annoying, and multiplied across the company, might be enough wasted time to notice.
Still, I'm generally bullish on them, overall.