As my 6th Generation Nano (the tiny one) can't play videos, and the machines at the gym will play video from iPods on a big screen, I decided to dig out my older nano for gym service. I did previously use this for many years until I decided to get the newer one. Can't really remember why; I just did. Anyway, I got back to using this one again. It's remarkably simple to use, as all older iPods were, and 16GB is enough for a few episodes of my favourite TV shows, and a reasonably long 'gym playlist' of music. I would use the iPhone for the gym, but it is too big and bulky, and I've seen so many of my friends' iPhones with smashed screens, so I thought I'd be better not to risk it.

The first thing you notice, it's a bit bigger and bulkier than the version that replaced it. As I'm solely using it for the gym, it isn't so much fun on the weight machines, or free weights, where it's size can make it a bit annoying, but it doesn't matter on the cardio machines (bikes, treadmills, cross trainers) where it plugs into the machine itself. It is compatible with quite a lot of different accessories, and luckily that includes my gym's cardio machines. I often get bored on a treadmill, so using this to have my favourite TV show to watch is pretty good. One thing I missed from the 6th Gen Nano was the Nike+ functionality, but it's a tradeoff between that and the video playback ability, unless I save up for the latest Nano, which I won't be doing as I have an iPhone.
For music playback, you can also utilise the built in speaker; but it's a traditional tinny thing like you find on a phone. Better off sticking to headphones, or getting a dock.

Outside of the gym, the only other notable function is the camera. But it's not very good, and seeing as you'll more than likely have your phone on you as well as your iPod, I don't see why you'd use it.

However, all things considered, I have gone back to using the 6th Generation Nano for gym service. Yes, it doesn't have the video functionality, but in all other respects, it is better. It's size makes it perfect for gym use, and having built in Nike+ functionality gives it the edge over the older one, despite it having the video option.