Out of the Box Projector Performance
Not everyone wants to spend lots of time playing with, adjusting or calibrating their projectors. Most want a projector that performs near or at the top of it's game, without doing anything to it. Although both of these projectors can be improved upon with a professional calibration, there are still differences in how well they perform "out of the box".
In the case of these two affordable 1080p projectors, they both happen to produce very good "out of the box" performance. I can't actually say that one is notably better than the other. Both, of course, can use some improvement, but many would be extremely satisfied, as is.
Projector Brightness is an area where these two projectors go their separate ways. The Panasonic PT-AE2000U is significantly brighter in best movie modes, and even more so, in brightest mode, meaning you can go with a larger screen, or do better at fighting some ambient light.
On the plus side for the Sanyo, is its Brilliant Cinema mode - although not as good as its best mode - Pure Cinema - it still looks very good, and some readers with PLV-Z2000's have reported that they can recognize some difference between the two modes, they favor Brilliant Cinema, as more than good enough, and far, far brighter. From a practical perspective, the Panasonic is much brighter than Sanyo's Pure Cinema, but definitely not as bright as Sanyo's Brilliant Cinema.
So, for those primarily interested in movies, that may balance things out a bit between the two. Still, the Sanyo's Bright mode is far less bright than the Panasonic's something like 40% less, which is significant. For those wanting to watch sports with some lighting in the room, the Panasonic definitely has the advantage.
Sanyo's Brilliant Cinema mode aside, figure the Panasonic, overall, for movies, and TV / sports, can handle screens about 15" more diagonal, with the Sanyo at its best on typical screens (not those with very high gain), of about 100" diagonal, while the Pansonic is comfortable on 110" screens and can definitely go a bit larger.
Overall Picture Quality
Slightly different but these two projectors both produce an overall picture quality that I described in their respective reviews as - "a pleasure to watch". No rough edges, even though neither of these can match some of the more expensive projectors out there.
Enthusiasts, I believe, will slightly favor the Sanyo Z2000 over the Panasonic PT-AE2000U, in this regard, despite it being less bright. The average consumer, primarily by virtue of brightness, I think will favor the Panasonic, but, again, not by a great deal.
For most folks, either of these will "knock your socks off".