Matthew Guay:
Bluetooth tethering. It sounds archaic and slow, but actually worked out better. And it wasn’t slow, either: the speeds were essentially the same as I typically get through 3G already, or around 1.5Mb down and 1Mb up. Comically, it was faster to connect. I always seem to have a somewhat tricky time getting my iPhone’s Wifi hotspot to show up in areas with tons of Wifi networks, but connecting via Bluetooth literally took two seconds.
He also says that it uses less battery power than Wi-Fi.
Update (2015-05-27): I just tried Personal Hotspot over Bluetooth and found that it was much slower than over Wi-Fi.
Battery Life Bluetooth iPhone Mac Networking Personal Hotspot Wi-Fi
Max Seelemann:
The most problematic part for us was understanding Apple’s NSFileCoordinator APIs and the many issues we had with it. The thing is: it looks simple, the methods are certainly simple and the documentation is written in a simple way -- but it’s use is everything but simple. In retrospective, we get the impression that the whole system seems to have been tested for Apple’s standard use only. That is, a user-managed single layer of folders, with occasional opening, saving and renaming of a few monolithic files. Pages, Keynote, traditional document-based apps. However, while the underlying APIs are designed and documented for broader use and more advanced situations, they soon start to fail if being used like that.
Bug Cocoa iCloud Mac Mac App Syncing