Although you could compare our reviews side by side, we decided to make it easier and include a breakdown of why we rated each product as we did. For further details, you can go directly to the appropriate section of each review by using the links below.
The one area of our reviews where TiVo beats Replay is in the Design section, reflecting TiVo's more-polished user interface. First-time users will likely learn to navigate TiVo more quickly than Replay, thanks to the former's natural-language menu commands. TiVo's To Do list, which specifies all upcoming recordings, is a useful tidbit that Replay lacks.
Replay's menus and navigation, while completely usable, are just not quite as intuitive and elegant as those of TiVo.
We rated the Replay's features better overall for a number of reasons. First, it has a progressive-scan output, so it can deliver high-quality video to HDTVs and other progressive-scan displays. Replay sports built-in Ethernet support and can therefore download program-guide information from a broadband connection instead of being restricted to using the phone line. It also boasts a 30-second, manual commercial-skip function and an automatic commercial-skip option that's somewhat less reliable. The Replay can also be programmed remotely over a Web connection.
TiVo has none of those features out of the box. The 30-second skip function is quickly programmable, as is the Ethernet program-guide download--once you've paid extra for a USB Ethernet adapter (see "TiVo tricks" for more). For a one-time $99 fee, TiVo now offers an upgrade called the Home Media Option, which, when coupled with a USB Ethernet or wireless networking adapter, enables a Series2 box to access music and photos on a PC's hard drive over a home network. This feature also lets you program TiVo over the Web and allows two similarly configured TiVos on the same network to share programming. Because it is an optional upgrade that also requires additional hardware, the Home Media Option did not factor into our Features rating. Instead, we examined it separately.
Since a DVR has to encode video into MPEG-2 and decode it for playback, both TiVo and Replay will adversely affect the quality of the picture. Most viewers won't notice the difference, especially with low-resolution cable, but high-quality sets such as HDTVs can reveal some of these flaws. Note that integrated satellite/DVRs (see "Other options") don't have to encode in MPEG-2; therefore, their video quality is usually better than that of standalone units.
Overall, Replay showed a slight edge in video quality over TiVo. Its progressive-scan, component-video output provides the best quality video that we've seen in a DVR, but it can be viewed by only progressive-scan-capable HDTVs. In S-Video mode, TiVo looked a tad sharper, but ReplayTV handled difficult darker images better.
The CNET rating is achieved by assigning each of the three review criteria--Design, Features, and Performance--a certain percentage of the score. For DVRs, we weight design and features with 35 percent of the score each, while performance receives 30 percent. We calculate the overall CNET rating by giving each category a whole-number score between 1 and 10. By this method, both TiVo and Replay are very good products, but ReplayTV is slightly superior.