Recording video and audio is a snap, and the results are worth your while. As long as you have the recoding adapter, you can record (MPEG-4/AVI with maximum 640x480 30fps) from a wide variety of sources such as DVD (it's Macrovision compliant, so you can't watch recorded files on any other device), cable, and satellite. Audio recording (PCM or ADPCM WAV) is similarly intuitive and effective.
Though the built-in recording scheduler works well enough, and you can download show schedules via My Yahoo, the process is not as smooth as you'd think. We'd love to see more integration (as Archos has done with Dish Network) so that you could get content more automatically and more intelligently. Still, the ability to record gives you a free source of good content.
The 604 can also play MP3, WMA, subscription WMA, and WAV files. Support for album art, bookmarking (for videos, too), ID3 tag-based browsing (via the ARC Library), gapless music playback, and the solid playlist creation highlight the 604's audio features. We were, however, disappointed with the quality of the newly added EQs. We do like the fact that upon connecting to a computer, the 604 gives you the option of UMS (PC hard drive) or MTP (Windows device) modes. Transferring to and from Mac (drag and drop) and Windows (autosyncing) were clean and quick.
The 604's revamped photo features are neat. One method for browsing is the thumbnail mode, where you get 54 thumbnails, which magnify as you pass over them. Slide-show transitions are professional, and you can zoom in multiple steps. I would say it's a great photo viewer.
How did the Archos 604 get so affordable?
Part of the reason the 604 comes in at $350 while the AV500 is currently $450 is the 604's lack of accessories. In order to record audio or video, you need to purchase one of two optional kits. The first is the Archos DVR Station, a dock designed to fit in with your entertainment system. This $100 kit (with a nice remote control) can record virtually any video source including cable TV, DVD player, camcorder, and so on, as well as line-in audio. It features virtually every input and output you'd care for, including S-Video in and out, component out, standard USB, and even SPDIF out. The other option is the more portable DVR Travel Adapter Kit ($70), which includes a four-inch adapter that snaps onto the 604's dock connector. It's easy to use and transport, but it lacks the depth of ports of the dock. The AV500 actually shipped with a docking pod, making it record-ready out of the box. So you're actually paying about the same if you add the recording hardware--not a bad move by Archos, since you can save some cash if you don't want to record. However, recording is one of the prime features of this "DVR," and our advice is to get one of the two kits when you buy the main unit.
What you do get in the package is pretty weak--a proprietary USB cable, earbud headphones, a 604 dock module (for use with the DVR Station), and a sad excuse for a case. Just the basics--you don't even get a power adapter as you are expected to power via USB. If you want AC power, you'll need to spring for the $30 Docking Adapter Kit, which includes an adapter that allows you to transfer photos to the 604 from digital cameras. So in order to match the $420 30GB Cowon A2's recording and photo-transfer features (not to mention an AC adapter), you'd have to spend a total of $450 (604 + Docking Adapter Kit + Travel Adapter Kit).

Sound quality is decent at higher volumes (bright highs, average low end, punchy mids). In our original review, we noted that the 604 had a layer of electric noise especially noticeable at low volumes--and it didn't have anything to do with the display. We have since updated the firmware to version 1.2.05, and it eliminated most of the noise, though we can still detect a tiny bit. Archos even added gapless playback of music files. Let's hope Archos continues with aggressive firmware updates.
Video piped out to a TV looks good (depends on your original file), though the presence of compression artifacts lead me to believe that the docking station with its fancy outputs might be overkill.
Processor speed is responsive--especially scanning through video, though there are some light pauses in the menu, like with the Cowon. Photos and videos load quickly. Battery life may not approach Cowon A2 levels, but we're still impressed with the rated 14 hours for audio and 4 hours of video. In informal testing, we got plenty more than 14 hours for audio. We'll update with our official battery-life results when they come in. The removable battery makes a huge difference--replacement batteries cost $30.

