For about the fourth Sony home theater projector review in a row, our calibrators (first Mike, now Eric) came back telling me that the Sony's best picture - Reference Mode - is almost dead on the money in terms of color accuracy without any adjustment. Excellent grayscale balance and no real need to tweak the individual colors (CMS). In all cases they (the calibrators) provided minor changes, but as Mike pointed out. He really couldn't see any obvious difference in the picture comparing the default to the minor adjustments - that is differences in color are barely noticeable. Of course there's some lamp variation, and that too will change over time. Bright TV is a little over-the-top, and a couple of the specialty ones aren't what you would want to use for movie viewing but overall none of the modes is ugly, and most look great for the job intended, such as tackling extra ambient light, or gaming.
In the small player (you can expand the image size), the first three images - of the ref - are showing Bright Cinema, Bright TV and Reference. The exposures were the same. I believe I had reference in it's default low lamp mode, which explains why its quite noticeably darker than the other two.
There isn't a drastic amount of brightness difference between the various modes when measured, such as between best modes like Reference or Cinema Film 1, and modes like Bright TV. In fact, the brightest modes are mostly about more "pop", accomplished by different sub-settings such as gamma, contrast enhancers, etc. Also the color temp of some are cooler than the ones more movie oriented. Still all are pretty well-balanced - no screaming greens, etc. I find I've been using Bright TV, for my sports viewing, with the Color Temp set to D75. Bright Cinema is warmer, and overall better for movies on HDTV etc., with ambient light present.
4K content is a whole different world, with the broader BT2020 color gamut and HDR. For that, I'm using User 1 based originally on Reference but with major changes: I have BT2020 running, and HDR on. There is no gamma with HDR.
Bottom Line - not a really ugly mode choice in the batch. You can choose from several modes when you are fighting some ambient light, or just want more "wow" and "pop" to the image. Still for great movie watching, you'll want to use Reference (with minor calibration changes as desired). That, of course is all about 1080p content.