After demo'ing the RS40 to a number of people, including some experienced a/v guys, I would like to share some of my thoughts/observations. I am no A/V expert, so please take as such:
The RS40 is excellent for 2D, but downright amazing for high quality 3D content. I did not buy the RS40 for 3D, but I am really glad I did.
I am very susceptable to motion sickness, but I have no problem with watching 3D on the RS40. About a third of the people start to get a little headache in the beginning. For the first several minutes, don't display fast motion content and don't let them get too close to the screen. Also, after a while you can train your eyes not to dart around and continually re-focus. It really helps to keep your eyes on the center area of the screen and let your peripheral vision work for the rest. Suggest that to them if they start to get a headache. After a while, you don't even have to think about it. One of the guys started out in the back row in watching Avatar 3D and ended up in a chair about 1x screen width for the last hour of the movie.
I, like others, often enjoy watching 3D closer to the screen. I watched Avatar 3d from about 1.2 x screen width which is about right for me as compared to about 1.6x for 2D.
I purchased Avatar 3D (at a ridiculous price) to demo to a group of a/v enthusiasts as well as watch myself. I planned to sell it afterward, but I don't know if I can - if any DVD is worth that much, Avatar 3D is.
I really haven't really decided if watching sports in 3D is signifantly better than 2D. I haven't watched enough to really decide. After the novelty wears off, it will be interesting to see what I prefer and by how much.
The JVC glasses were considered notably better by these guys (brightness, etc.) than the XpandX 103's. Since there is just two of us in the house normally, I will keep 2 JVC glasses and 2 XpandX glasses.
Due to the brightness issue with 3D as well as general viewing, having a batcave like mine (including black ceiling!) was, in hindsight, an excellent decision. I will probably be replacing my lamp sooner than I did with my RS1. I have a light meter and will be measuring the change over time.
Demo material - I haven't watched all that have been suggested, but Under the Sea and Avatar 3D are all that I need, except for sports that I have recorded on my DVR (golf, hockey, football, basketball, X games highlights). There are also a couple of scenes from programs on the DTV 3D channel that are pretty good for demo use.