3D processing has improved to the point where crosstalk artifacts are no longer the issue they once were, and both of these projectors deliver exceptionally clean and stable 3D. One salient difference between the 5030UB and the AE8000 is in 3D brightness--the 5030UB delivers a 3D image that is about 40% brighter than the AE8000. That sounds like a lot, but this needs to be kept in perspective. To obtain equivalent 3D image brightness from both projectors, if you were to set up the 5030UB on a 100" diagonal 16:9 screen, you would need to use an 85" diagonal with the AE8000. (A 100" screen has about 40% more surface area than an 85" screen.)
The most obvious downside to 3D with any projector is the glasses which are often uncomfortable and visually distracting. In worst case scenarios you feel like you're wearing a helmet. Many people avoid 3D simply because the glasses can be annoying, so this essential component of the 3D system warrants more attention than it normally gets in a review.
Fortunately, the Epson and Panasonic 3D glasses are both relatively light-weight and better than many of the glasses we've seen. However, their differences are noteworthy. Panasonic's 3D glasses have a light, natural feel, almost as if they were normal sunglasses. The frames are constructed with an arc that causes the lenses to be positioned relatively close to the eyes. The benefit is that, at least when I look through them, the lens frames do not intrude very much into my peripheral vision. So I don't get as much of a sense that I'm wearing "special glasses."
Epson's 3D glasses are not any heavier than Panasonic's, but they are physically a bit larger and the frame across the bridge of the nose has less of an arc, so they have less of a wrap-around effect. This causes the lenses and frames to sit at a greater distance from the eyes, which in turn makes the frames of the glasses more visible in one's peripheral vision. One is therefore is more conscious of the glasses on the face. When viewing a 3D screen in the dark this sensation is mitigated somewhat. Nevertheless, Panasonic's glasses are designed to be less intrusive in the user's field of vision, thus making it easier to forget they are there.
As a side note, Panasonic's 3D glasses also have an optional 2D switch that displays left-eye content to both lenses, essentially allowing someone to watch a movie being display in 3D in 2D. Why you wonder? Because some folks just don't like 3D no matter what--it makes them seasick or gives them headaches. The 2D/3D switch allows a family or group of friends to all watch the same 3D movie in a social setting, and the glasses let anyone who does not like the 3D effect to turn it off.
On the other hand, Epson's 3D glasses have an advantage over Panasonic's in that they have RF communications while the AE8000 used IR. RF has the advantage of not requiring line of sight connection, and it doesn't have the potential to encounter interference from other equipment in the room that you might be controlling via IR.