Brightest NZ90 with average to poor battery life.
next brightest NX80 average battery life.
Palm T?C and Zire 71 equal brightness but the battery life very good even with web surfing on the T/C.
My Zodiac 1 is same brightness as NX70v. Both have good battery life. The Zodiac has a very nice color tone and is without the Clie "blue" tint. Like the Palms it has more of a neutral or earth tint.
My old NR, is brighter than my old 615 T and had ok battery life. My daughters SJ22 has same brightness as NR. Never owned a 665. The T/T almost as bright as the NR but better outdoors than most others and this one has a good battery life. My 515 rather dim by modern standards with average battery life but very good outdoors in bright sun. My old 505 was horrible for color, brightness and battery life but good outside.
It's funny but the brightest screen I have is in the iPAQ 3955 and the best screen was in a Zire 71 I gave to a friend. It was perfectly "paperwhite" and wonderfully bright. I keep all my devices on the brightest settings and batttery life can be so-so. The best battery in all of them seems to be the T/C battery with the Zodiac a close second. Actually the best battery life was to be found in my Palm 111xe. It lasted all month on two 3a batteries. I miss that a lot. There seems to be a lot of variation in screens even among the same model and issue. Clie seems to produce the best screens in the NX, NZ series with little variation in the ones I have owned. The T3 that I briefly owned seemed to have the most variation in screen quality and I returned it after several weeks of frustration over dim screen, color distorts and battery life. If I had to just pick one right now I'd go with the Zire 71, bright screen, reasonable battery and just plain fun. Didn't mean to run on.