Lens Shift, Lens
Both of these projectors offer 2:1 zooms. Both have more than enough range to allow the vast majority of users to place the projector a a shelf in the back of their room, if so desired, instead of ceiling mounting or placing it on a table. Lens shift is another issue. Lens shift allows you flexibility in where you place the projector vertically (and horizontally - although that is not normally an issue). With the Panasonic you can place the projector vertically anywhere from slightly above the top of the screen (about 8" to a foot) depending on how the zoom is set), to an equal amount below the screen when on a table.
The Sanyo PLV-Z4 projector has more range in the lens shift. So, for example, if ceiling mounting, you can have it further above the screen (by about a foot) than the Panasonic. This may be a slight advantage in most rooms, but if you have a high ceiling you may really like this advantage. For example, if you have a 12 foot ceiling and the top of your screen surface is at 8 feet, then the Panasonic would have to hang down slightly more than 3 feet, while the Sanyo would only have to be mounted about 2 feet from the ceiling, making it less intrusive (when the lights are on). The WIN goes to the Sanyo PLV-Z4, in this catagory. Also I like the Sanyo's separate controls for vertical and horizontal lens shift, better than Panasonic's joystick combined control. The Sanyo Z4, I should note, (like the Panasonic projector) now has a lens shift lock. Some owners of the older Z3 reported that the lens shift would slip, resulting (if ceiling mounted), in the image moving a few inches up over time, requiring the user to adjust it from time to time (or tape the controls down). This is no longer an issue, with the Sanyo Z4 projector.
Panasonic's PT-AE900u projector offers a remote with a better layout, and, in fact it's a learning remote that you can program to control your other home theater devices. (I did not review that aspect of the remote.) The Panasonic is fairly long, and controls are well organized with plenty of spacing between buttons. The backlight is nice and bright.
The Sanyo Z4 projector's remote, by comparison is small and more packed in. What really bothered me, though is it seems to have a more limited range. When I test both projectors at my house, I'm sitting about 11 feet from the screen and the projector is about 6 feet behind me. With the Panasonic projector's remote, I had no trouble bouncing the IR signal off of my front wall, and screen to control the projector. With the Sanyo, it was so hard to do that, that I resorted in pointing the projector over my shoulder back to the Sanyo Z4.
Now there are a couple of solutions. First, you may opt for a good programmable remote to control all your devices which then makes the range of the Sanyo's remote a moot point. The other point - If your room and screen are smaller, this may not be a problem at all for the Sanyo Z4 projector's remote. Overall, though The PT-AE900u is the clear winner when it comes to remotes.
Both home theater projectors have well thought out menu layouts. I found both to comparable. No winner here.
Both are pretty good, both pretty much step you all the controls and most of the features, and both, while listing your options for the many adjustments, don't go into enough explanation as to the advantages, etc. of using many of those choices. In other words both manuals are good, but could be even better.
Both home theater projectors have two component inputs, one HDMI, an S-video, a composite video and a computer input. If ever there was a tie, this is it.
Sanyo wins this one. The Panasonic looks more industrial, the Sanyo is nicely finished with soft edges. Also the Sanyo has a motorized door that closes, covering the lens when the projector is off. Nice touch, and it keeps dust from collecting on the lens when the projector is off (which of course is 80-90% of the time for most owners.
Since Sanyo does not rate the life of their lamps, this is a hard one to call. I'll have to play a hunch here, based on dealer feedback on the older Z3 projector. While lamp is rated 2000 hours in full power, many lamps fail long before that time. The Panasonic claims 2000 hours in full power and 2700 in economy mode. That's pretty typical. I suspect that the Panasonic lamp - on average - will last longer than the Sanyo, because I used to hear a fair amount about Sanyo lamps not lasting as long as anticipated on the Z3. Purely guesswork.