I bought an Anker T320 bluetooth keyboard to use with my iPad, mainly because it had such good reviews on Amazon. It's an amazingly good keyboard! It's really light – much smaller and lighter than the Apple bluetooth keyboard I was using before. It charges via mini-USB. The keystroke action is excellent. I am very happy with it. Here is my Amazon Affiliate link to the keyboard should you want to buy it: Anker® T320 Ultrathin (4mm) Wireless Bluetooth Keyboard for iOS (iPad Air, iPad Mini 2, iPad 2 / 3 / 4), Windows and Android 3.0 and above OS with Built-in lithium battery / Aluminum Body.
The past few days I've been bringing in my new WIFI-only iPad and trying to use it tethered to my iPhone 5. It's been a frustrating experience so far. I've found that it works OK when the iPad is first tethered to the iPhone, but shortly thereafter the internet connection seems to drop out on the iPad, even though the iPhone is still reporting it to be connected OK.
For the last month I’ve been doing a contract at Canary Wharf for HSBC. In an effort to minimise the amount of stuff I carry, I’ve just been taking my iPad into work with me. I’ve really missed having my home emacs environment available.
Last night I was thinking about this and I decided to get a bluetooth keyboard I could leave at the office. I can ssh from my iPad to one of my Amazon cloud instances, and have an emacs / development environment set up there. Consequently I bought a Cerulian Technology Mini Wireless Keyboard. It was really easy to connect to my iPad, but the keyboard is quite cramped to type on. The tab key especially is miniscule, so not great for Python coding. It’s still the first few hours of use, but I’ll keep using this and see how well it works over the long term.