Received one of these yesterday and overall I am very happy with it as a product. My main reason for purchase was to supplement disk space on my work issue iPhone 5 since they only supply a 16Gb model. After using this FileHub, I can see my only buying the base model of iPad in the future instead of my current 64Gb model. Why spend the extra £120 for a 64Gb model when the 16Gb and this device will give me what I need!
A few observations.
IOS app. Works 100% for me every time. This is the latest version of the Airstor app and device firmware. It always connects and all transfers I tried completed successfully without issue. My main use for the device is movies and photographs when I am travelling. The app will play back IOS supported movies without issue. Unsupported movies will give you the option of downloading. Once downloaded, the app will give you the option to open in another app so provided you have a media player that supports the file you are trying then this is an acceptable way of getting access to the media - you need to download and then transfer to the supported app instead of just streaming. The alternative is to use an app that supports streaming and SMB - see below.
Download speed. While the transfers are way fast enough for streaming a movie, I like the option of downloading to my choice of app for playing locally instead of streaming. I haven't timed this properly yet but regardless of the source being a normal USB pen drive or a high speed SD card, I was only getting transfer speeds of a bit over 1Mb/sec. Not a deal breaker but it was taking around 10 minutes to transfer a 700Mb movie file.
Movie streaming. I was streaming 720p content to my iPhone 5 and it was streaming flawlessly without a single issue. This was both with MP4 in the Airstor app and also MKV in the nPlayer app.
SMB sharing. Using nPlayer as my media player of choice, I couldn't find the FileHub doing an SMB search. I could set it up as a manual connection using the IP address of 10.10.10.254 and username of admin. This would see the FileHub but as soon as I tried to access any content folders, I would get a connection refused error. I set up a password for the FileHub and rebooted it and tried with my manual connection again. This time, nPlayer could navigate the folders and stream perfectly or download the file for local playback. It seems you need to set a password before you can use SMB.
Disk format. I tried an SD card formatted as exFAT and this could not be read by the FileHub. I'm not sure if exFAT would work with a USB drive or not but I see this as a real limitation of the FileHub. FAT and FAT32 work fine and looking at the firmware notes, it appears NTFS does too.
Photographs. At a push, this device could work as a replacement to the camera connection kit. Inserting an SD card or USB drive (CF card using a USB card reader) lets you browse your images and select specific or all images. You can upload these to your IOS device, the Airstor app lets you navigate it's own internal folder hierarchy and select a location. You could then open these images in your camera roll although I'm not sure if you can open multiple images in one go. This isn't as elegant a solution as the camera connection kit and involves an extra step but it is at least functional. What is probably of more use is the ability to upload images from your IOS device directly to an SD card or USB drive say when on vacation either as a backup or to allow you to then free up that space on the IOS device. You also have the option of using this method to share these files with other users although there are already apps that let you do that directly via Wifi or Bluetooth and airdrop in IOS 7 will also let you do this sharing function.
For me, this purchase is a no brainer if you want to travel with a lot of media and are running short on space on your IOS device or if you have just the base model to start with. It also makes sense for a whole family travelling with IOS devices as you can treat this as a portable NAS device and share content to all clients. You can easily swap out SD cards and USB drives when required but because it is a full sized SD slot, you can insert a large capacity SD card fully so it sits flush with the unit and use it as a form of semi permanent storage. You can pick up Ravpower Wireless Filehub and a 64GB SDXC card for less than half the price it would cost you to upgrade from a 16GB to 64GB iPad. You may lose a little bit of convenience with the limited internal storage but you would gain much more practicality and flexibility as well as this being a one off cost so you would save even more each time you bought a new iPad for example.
I'm a fan and the only two things I would love to see are improved transfer speeds and exFAT support.