The results of SDE are very different between these two projectors. The Panasonic PT-AE900u projector uses what they call Smooth Screen LCD panels, and their pixel structure is barely visible compared to typical LCD panels (like the Sanyo Z4's). The bottom line here, you can sit much closer to the Panasonic, than the Sanyo Z4, as the Panasonic projector's panels behave more like DLP chips than LCD panels. Screen door effect has been considered one of LCD's weak spots in performance.
I found that you can sit about as close as 1x or 1.1x (better) screen width with the Panasonic (that would be about 8-9 feet (9 feet is safer) from a 110" diagonal screen. With the Sanyo Z4, I would recommend 1.4x - 1.5x screen width, which would be about 12-13 feet back, at the closest. Those particularly adverse to seeing any pixelization at all in bright areas (and text) where they are most visible, wll want to sit a bit further back from both.
Personally I like to sit fairly close (but I am the exception), in fact I sit just over 11 feet back from a 128" diagonal screen. At that distance the Sanyo Z4's performance was unacceptable because of SDE. When I was watching ESPN Sunday Night Football in Hi-Def with a friend, and the Z4 was filling my screen, my friend (used to my normal DLP projector), immediately asked "what is wrong with the picture?" To watch from our normal seating distance, I had to adjust the zoom to about a 92" diagonal screen size before SDE ceased to be a problem. At that point, my friend agreed that the distortion he had seen was gone.
In other words, for me, after considering all the other differences between these two projectors, my preference for sitting closer to the screen, is enough, all by itself, to be the deciding factor in my buying the Panasonic over the Sanyo. I think this should be a major consideration for most home theater projector buyers. Afterall, it's the theater effect we want, in buying a projector instead of a 65" "big screen TV".
If you like a very large image (relative to your seating distance) this is a huge win for the Panasonic PT-AE900u projector over the Sanyo Z4 projector. If you like to sit half way back or further, in a movie theater, then, either projector will do equally well, but if you like being 1/3 back in a theater, then in your home, your seating is probably too close for the Sanyo.
Vertical Banding: What? With LCD panels, sometimes - mostly when you have a large area of neutral grays (fog, some backgrounds) you can see some vertical banding. (fine vertical lines) Worse, it seems to vary from projector to projector. With the predecessors of these two projectors - the Z3 and AE700u, vertical banding was a well known issue, that in some cases could be corrected.
With these two new models, however, it seems to be less of a problem. Neither of the two PT-AE900u projectors, nor the Z4 that I have used in the last few weeks, exhibited any vertical banding that would be visible at any normal viewing distance. (I could see it on the Panasonic at a distance of about 3 feet - on about a 100" screen size, on the Z4, it was visible slightly further away. I tried to capture the Z4 projector's vertical banding on my digital camera for the review, and it couldn't even pick it up so that you would be able to see it.
So, it is possible that you might get a projector with visible VB, but it seems very unlikely. The effect is likely so slight, that, even if there, you won't ever notice it. However, should you actually have a unit where it is visible and annoying at your seating distance, Sanyo provides a way to adjust it, that is in the manual. With the Panasonic projector, it can also be corrected but the adjustments are in their service menus, which means - stay out, and get a dealer (or Panasonic) to adjust.