OK, OK. Point taken! However I still need to test my affinity to rainbows. I will pick up the w770 for comparison.
But let me ask: how much better would a 1070 or a Optoma 131 be than the w770?
In terms of resolution, the w1070 and Optoma 131 would certainly be better. In terms of contrast, the w770 is just as good. The reviewer on trustedreviews.com stated he thought the w770 had better contrast than the w1080st (short throw version of the w1070).
"If you can manage to find an extra £120 or so, then you could consider the BenQ W1080ST instead as it carries a full HD resolution - though actually in some ways, especially contrast, the W770ST’s pictures arguably look slightly better than those of the W1080ST." -Trusted Reviews guy
If resolution is a top priority and you have the cash, why not go for the w1070. If you would rather not spend more, I don't think you'll be disappointed with the w770.
On rainbows, I sold my first dlp projector because I was annoyed by them. I had an Epson 8350 (1080p) before selling that for the Benq. I bought the w770 knowing the color wheel speed is only 2x. Call me crazy, but I "trained" myself to stop seeing the rainbows, and I'm sensitive to them as evidenced by my first projector experience. You might not even notice them, most people don't. If you do, I made my eyes follow the picture being projected and ignored the rainbow artifacts. Eventually, I stopped noticing them.
Hope this helps. Whatever you decide on, enjoy the home theater!