Pairing Bluetooth headphones or speakers is a simple process. You tap the Settings icon on the nano's screen, tap Bluetooth, and then turn Bluetooth on if it isn't already. When the name of your headphones or speakers appears in the list, tap it, and enter a pairing code if necessary. (In my testing, most didn't require a code, and those that did used 0000.) Your headphones or speakers then appear as Connected in the Bluetooth screen. The process is, again, nearly identical to the way you pair with Bluetooth devices in iOS. You switch between Bluetooth output and the built-in headphone jack by tapping a little Bluetooth icon on the Now Playing screen and then choosing either iPod or the Bluetooth device's name.
I tested the new nano with a handful of Bluetooth headphones and speakers, and all paired immediately. Over several days of testing, I didn't hear any dropouts or static. (I wasn't able to test the new nano with a Bluetooth heart-rate monitor.) I was also impressed by the nano's Bluetooth range, as I was able to listen through Bluetooth headphones from over 20 feet away. Note that one drawback of Bluetooth headphones and speakers is that you can't use them when listening to the nano's FM radio, as the radio requires wired headphones--it uses the headphone cable as an FM antenna--and connecting wired headphones switches audio output from Bluetooth to the headphone jack.
...but no Wi-Fi
On the other hand, the new nano doesn't get the other common form of wireless communication: Wi-Fi. Just a couple short years ago, I wouldn't have mentioned this as a drawback, but with Apple's recent emphasis on cloud features, and especially considering that many Apple customers have iTunes Match accounts that make their music accessible from anywhere with an Internet connection, Wi-Fi would be a handy feature in the iPod nano: Forget to sync your updated workout playlist? If your gym has free Wi-Fi, you could just access your iTunes Match account to download the latest track additions. It's possible the Wi-Fi circuitry and antennas couldn't fit in the nano's wafer-thin body, or that adding Wi-Fi would have impacted the player's battery life considerably, or that adding Wi-Fi would bring the nano one step closer to the iPod touch. But I think a wireless data connection of some sort is the obvious next step for the nano and other dedicated media players. Next year?
This, that, and the other thing
The nano continues to offer a slew of minor features that are sure to be used heavily by certain people and completely ignored by others--but that taken together make the nano an impressively well-rounded gadget. As with all recent nano models, the latest version offers a voice-recording feature. You can still use the nano as a flash drive by checking the Enable Disk Use box when connected to iTunes. A built-in pedometer tracks your steps and distance when walking, and the seventh-generation nano supports Nike+ and NikeFuel for tracking your workouts when paired with a Nike+ sensor or a Bluetooth-enabled heart-rate monitor. (As with the iPod touch, you don't need an iPod-attached dongle to connect to the sensor--the sensor can pair directly with the nano.)
As mentioned above, the nano continues to offer an FM tuner for listening to the radio (or for listening to broadcast audio from the TVs at many gyms). In my testing, the new nano seemed to get slightly better reception than the previous generation. It offers the same RDS (Radio Data System) display and the same capability to pause live radio for up to 15 minutes, skip back in 30-second increments, skip forward in 10- or 30-second increments, scrub through buffered audio, and tag songs for latter syncing and purchasing through iTunes.
Apple claims the new nano offers up to 30 hours of music playback on a full charge (the longest ever for an iPod nano) or up to 3.5 hours of video playback (shorter than the fifth-generation nano's claimed 5 hours). Apple also says you can charge the nano to 80-percent capacity in only 1.5 hours; it takes 3 hours to get a full charge. I've spent much of the past few days connecting and disconnecting the new nano to and from various computers, so I haven't yet had a chance to do any controlled battery-life testing.
Looking back two generations, compared to the 2009 iPod nano, the latest model is missing a video camera and a built-in speaker, but given the downright poor quality of those features, they weren't a big loss with the 2010 model and I don't lament their omission here. Other iPod features that still haven't found their way back from 2010 elimination include games, alarms, and information syncing (notes, calendars, contacts). Again, with the possible exceptions of alarms and games--and possibly not even those--I think it's safe to say that these features weren't widely used.
Finally, the audio buffs out there are surely curious about how the new nano sounds (and they're cursing me under their breath that audio quality has been relegated to "finally" status). The iPod nano isn't an audiophile gadget, so I didn't treat it as such. But I did test the new nano over several days with a range of headphones, including several higher-end models that work well with low-power headphone outputs. Overall, I found no glaring issues with sound quality. Compared to the 2010 iPod nano, I noticed only very minor differences when comparing the same uncompressed music tracks played through the same headphones. The new model seemed to sound ever-so-slightly clearer with slightly better bass response, but the differences were small enough that I can't make a definitive claim.
In terms of audio formats, Apple says the iPod nano supports AAC (8 to 320 Kbps), Protected AAC (tracks purchased from the iTunes Store), AIFF, Apple Lossless, Audible (formats 2, 3, 4, Audible Enhanced Audio, AAX, and AAX+), HE-AAC, MP3 (8 to 320 Kbps), MP3 VBR, and WAV.
Those who loved the previous iPod nano's built-in clip and square shape--especially folks who used the nano as a clip-on workout companion or a makeshift wristwatch--will lament the latest model's taller, clipless design. But as handy (or, if you will, hands-free) that clip was--and for many people it might be useful enough for Apple to consider a similar product separate from the nano line--dropping it let Apple make the new iPod nano remarkably thin and light. In addition, the larger screen and physical buttons dramatically improve the nano's usability, and the addition of Bluetooth functionality is a big win for active use. Clip aside, it feels like this is what last year's iPod nano wanted to be: Familiar, but better in almost way than the one before it.
This year's model, in fact, addresses most of the major complaints I had about the sixth-generation iPod, taking what was good about that model and incorporating features and design elements from both Apple's iOS devices and the 2009 iPod nano. The results is, in my opinion, the best iPod nano yet--as long as you don't want to wear it on your wrist or clip it to your workout clothes. It's still missing a few features present in older models, and Wi-Fi--along with iTunes Match--would truly set the nano apart from other media players on the market, but the 2012 iPod nano is an impressive device that's easier to use than any nano before it.
That said, the big question facing the iPod nano line these days is a simple one: Why? If you've got an iPhone or an iPod touch (or a similar non-iOS smartphone), you've already got a solid music-listening device, and there's a good chance you carry that device with you most of the time. If you don't already have such a device, for $50 more ($199) you can get the previous-generation iPod touch which, though not as small, is more capable in every way. At $99, the nano would be easy to recommend, but at $149, it's a tougher sell. If you're looking for a dedicated media player to save your smartphone's battery for calls and apps, or if you want something smaller and lighter while working out, or if you've got a child who just wants a media player, the nano is a solid choice. But the iPod touch is encroaching on the nano's territory, and the days when you needed a separate iPod are fading fast.