Note that, as the drive is formatted using FAT 32, you can't store files that are larger than 4GB on it. You can reformat it into NTFS, but then it won't work with a Mac.
The Wi-Drive can stream basically all content supported by the iPad: videos (M4V, MP4, MOV, Motion, M-JPEG, AVI), audio (AAC, MP3, WAV), photos (JPEG, BMP, TIF). It can also display documents for many popular formats (PDF, DOC).
As a USB 2.0 portable the Wi-Drive was rather slow in my testing, averaging around 9MBps for writing and 17MBp for reading. This is likely because its internal storage is made of a low-performance solid-state drive, similar to that of thumb drives. Nonetheless, as it has limited capacity, it's quite fast to fill it up with data.
As a storage extender, however, it worked very well and offered good range. I was able to stream music and photos from up to 150 feet away, though it worked best at 75 feet or closer. The Wi-Drive's iPad app also works in the background, allowing users to listen to music stored on the Wi-Drive while doing other things.
In my trial the Wi-Drive also worked very well with any existing Wi-Fi networks and allowed its connected clients access both its content and the Internet at the same time, seamlessly.
I was a little disappointed with the Wi-Drive's battery life, which was just around 2.5 hours of continuous streaming in my testing. Considering how small it is, however, this was to be expected. The drive gets rather warm after running for an extended amount of time. It's not hot enough to be alarming, but warmer than you'd want to keep in your pocket.
(Longer bars indicate better performance; measured in MB per second)
The Kingston Wi-Drive would make an excellent portable drive/storage expander for a tablet if it supported USB 3.0 and offered larger capacities. At its current state, however, it still makes a very good and convenient companion for those who travel and don't have a huge amount of content that needs to be carried on the go.