First, when I compared the PE7700 side by side with the PE8700+, I paused at the very opening where there is nothing but a scene of stars.
Before I go on, remember that the PE7700 is brighter, so the images of the 7700 in the side by side seem brighter, and lacking blacks. This is just the result of the automatic metering. Either one looks overexposed, or the other, underexposed. In cinema mode, both projectors were almost identical - you could see the same number of stars. When I switched to Home Theater mode, the number of stars must have tripled. (PE7700 is on the right on both star scenes), yet the overall darkest areas seemed to be the same. Nothing I could do with the PE8700+ could accomplish what I saw here. I could get more stars, but my "blacks" ended up much lighter gray, and I lost the feeling of stars on a "black" backdrop. I suspect that this enhanced performance is the result of the "Sense-Eye" technology BenQ claims for the PE7700 but hasn't yet divulged what it really does, other than marketing hype, as the settings in terms of color, brightness, contrast, etc. change very slightly between the two modes.
The next setting is Family Room, and this setting is obviously designed to combat having a significant amount of ambient light. In fact among other things, this setting shows color boosted to +9, which is a significant change for this projector. I found the Family Room setting to be "a little too much". It will definitely help a lot with the ambient light but flesh tones and other subtle colors are definitely, and obviously less natural.
The other two modes: Photo mode, which is more contrasty, and Gaming, which is very dynamic (and far, far, from natural flesh tones.)
As mentioned above, both Cinema and HT modes produce excellent color balance. I made only minor adjustments with the Avia disk. In general the adjustments were less than the differences between most content and sources. You can see a couple of comparison images between Cinema and Home Theater modes. They are close, but the Home Theater mode on the right, in reality is a little "lighter" in terms of gamma. (Of course my digital camera adjusts for slight differences in overall brightness, tending to minimize the actual difference you see when switching back and forth. Both look good.
Night scenes on the BenQ PE7700 projector were especially dynamic looking. To a degree they remind me of the Panasonic AE700u which stretches the dynamic range by darkening dark areas, while brightening very light areas (without blowing out detail). The effect isn't as dramatic on the PE7700, but that's probably good, as the Panasonic can deviate noticeably from the true image (although people like it). The enhancement here is more subtle, but every bit as pleasing.