I've been starting off this section with a comment on the physical appearance of the projectors being compared. In this case, the JVC, well, is just a clean, elegant looking unit, with shiny piano finish, and tastefully added gold trim around the lens, and a thin line on the top and sides. It's hard to argue with the styling. (note, the JVC HD950's trim is silver not gold, so just as good looking, but perhaps not as classy).
The Epsons are boxier. They've made an attempt at styling, but I seriously doubt anyone will give them an award. The 9500UB comes in shiny black finish simillar to the JVCs, but the 8500UB is white with silver trim. The JVC projectors are definitely a full size larger than the Epsons, which are about "average" in size.
OK! With that out of the way, we can get into the more important, non-aesthetic differences.
Both brands projectors have their lenses offset from the center. While the JVC lens is recessed, (and hidden behind a motorized door, when the projector is off), the Epsons have a large lens barrel sticking out.
As mentioned above, the JVC has motorized focus, zoom, and lens shift, a nice touch that makes setting it up easier. The Epsons lens is completely manual.
The JVC has its control panel on the top, and it's nicely laid out. Epson puts theirs on the side (right side if viewing from the front). That's a minor difference but I prefer the JVC layout. Of course after initial setup, we all rely on the remote control, not the control panel.
JVC has their input panel (cable connections) on the right side running from front to past half way back. The Epson panel is in the back. Some folks will favor the back location of the Epson. Historically, most projectors do have their input panels on the back. The disadvantage to that is that you need a little extra room behind the projector for cables to stick out. Others will favor the JVCs side solution, but that may depend on your room. If you enter the room from a projector's side, you'll prefer that the cables come out of the side you can't see. In my own setup, we enter the room facing the left side of the JVC, so I like, (my wife loves) that the inputs on the right, and out of sight.
None of these projectors (if ceiling mounted) require that you unmount the projector to change the lamp - a very good thing!
Epson and JVC projectors are designed to work well, whether ceiling mounted, shelf mounted, or on a table top (unlikely as it is that people will put them on a table "permenently).
Both projectors have two infra-red sensors for their respective remote controls. The Epson Home Cinema 8500UB and Pro Cinema 9500UB have a well laid out remote control with excellent range. One of my biggest complaints last year, about the JVC DLA-RS25 and HD750 is that their remote control was underpowered, and has very short range. I have the RS25, and I find it annoying. I have to point the remote backwards and up right at the projector. I've never once gottent a successful bounce of the screen/front wall. The good news, JVC fans, is this year's JVC remote has excellent range. It was nice as long as I had one of the new JVC's here, I put away my RS25's remote and used the RS25 (or RS15, or RS35) remote with my RS25.
Both brands of projectors have identical selections of inputs. There are 2 HDMI inputs, fully HDMI 1.3 compatible with support for Deep Color, 24fps, CEC, etc. Both offer one component video input (3 RCA connectors), and an analog computer input that can be instead used as a second component video input. Both have a 12 volt screen trigger.
Top image: JVC DLA-RS25 cable connection area. Lower image: Epson Home Cinema 8500UB connections