If you've opted to fit a hard drive to the A-100, it can join your home network and you can simply copy files to the disk for playback later. You can also connect to the A-100 via FTP, which might appeal if you want to send files to it from a laptop or even from another machine on the Internet. If you don't fit a hard disk, then by far the best solution for you will be to use USB storage -- either a memory stick or external hard drive.
For a device like this, it's quite important that the user interface is simple and easy to use. Popcorn Hour has done a good job here. When you first turn the machine on you will be presented with a simple screen. From here, you can select to use video, audio or photos. There is also a link to select the media source (USB, hard disk or network device), access the Web services or configure the box.
There are so many features it would be impossible to mention them here, but it would be remiss of us not to mention the A-100s built-in BitTorrent client. To use this system, you simply browse to the Web interface of the device, upload the .torrent file and hit start. The box does the rest.
Picture quality on the A-100 is superb as long as the file you give it to play is of high quality. Trailers from apple.com looked simply stunning, as did our DVD clips. The best results were from HD material.
Sound quality is great too. Again, the quality will depend on the type of file you are playing, but the A-100 will relay Dolby Digital and DTS out via the optical audio output. If you've got an AV receiver, you'll get full 5.1 surround sound.
If you're planning on using the A-100 for music, you should be aware that the audio codec support isn't as good as the video support. The usual suspects are here, including WMA, MP3, AAC (unprotected) and WAV. After a firmware update, FLAC is supported: boxes bought now should include this feature. No OGG support as yet, sadly.