You are asking two very different questions.
On quality, it comes down to image sharpness vs. contrast and black level. By all accounts, contrast and black level is a more important factor in image quality than resolution as long as resolution isn't significantly different. It's also worth noting that the Sony does not support full 18Gb/s HDMI 2.0, but it is limited to about 13Gb/s. This means it can't support 60Hz gaming or future video at 4K with HDR the way that the JVC models can. For the money, I think the JVC is a better buy at this time. It's not true 4K, but it is the better image. If I had the Sony, I wouldn't complain. But, I would prefer the JVC, and not by a lot, just a little. In your opinion, the JVC has a better picture than the true 4k content that the Sony can display?
Now, I'm guessing you have a really wide wall that just doesn't support a 16:9 screen, so you really are forced to use a 2.35 screen instead. If that's not the case, just get a 16:9 screen and call it a day. Using a 2.35 screen is not the 'preferred' way to go, it's a choice, and it requires more effort during use than just getting a 16:9 screen. If you hate the black bars, you can get masks for your screen to take it to 2.35 if you want to. My room is 13.5 feet wide. It has room for a 16:9 but just like the look of the widescreen. I understand that only certain movies will benefit.
Remember! The ability to switch between 2.35 and 16:9 content is required. All HDTV material, sports, video gaming, and some movies are in the 16:9 format. Only movies are 2.35, and not even all of them.
But, if you get a 2.35 screen, then you must either:
A: Get an anamorphic lens of high enough quality to support 4K resolution. That's about $5,000 from Panamorph, and you will need a sled of some sort to move the lens in front of and away from the projector for 16:9 content.
B: Use the zoom method. That is, zoom the image out so that only the center part hits your 2.35 screen, then zoom in, and make the image smaller, to fit the full resolution of the projector into the 16:9 space.
Option 'B' is the more typical way to do this nowadays because it saves you a bunch of money and really is very close in quality since you aren't double scaling the pixels.
So, you would want/need a projector with motorized zoom, focus, lens shift, and with memory presets for that setup to allow you to recall the different screen sizes. You also must place the projector in the range allowed to hit both screen sizes (16:9 height and 2.35 width).
The Sony LACKS this feature for no reason at all. This means that you must manually change the settings everytime you switch from 2.35 material to 16:9 material. It is a complete deal breaker if you really are stuck using a 2.35 screen. So, I would get a 16:9 screen with the Sony for sure. Yes this sucks.
The JVC has motorized lenses with presets so you can do this with a 2.35 screen quite easily.
One more point for the JVC if you are using a 2.35 screen.
