Results of LCD investigation
I ordered a couple of Optrex STEP character LCD displays from [DigiKey] to compare image quality after some bad experiences with LCDs (of various devices) in cars. I wanted to see if we can do better than generic a back-lit LCD.
After writing some control code for a ATMega128 dev board I had laying around (reading busy flag in 4bit mode is interesting...) and making some custom characters to pretty things up (useful for arrows, and symbols), I connected the displays and took some representative photos. They all look a little better in person, particularly in the sunlight - my photography skills aren't up to this task.
Anyway, the main thing here is that the Optrex STEP displays are visibly better in all conditions, particularly the crispness and angle of viewing. Only downside was a just-noticeable flicker in sunlight from the custom characters (visually similar to CRT monitor flicker) on the white on back display.
Under inside conditions, black on white looks great, with widest viewing angle range... I'd compare it to VFD. In direct sunlight however, the transflective black on white display looks better, and it doesn't matter how bright the sun gets. For most folks, the transmissive STEP display looks best (green backlight is also an option). If you expect direct, bright, sunlight, transflective is tops: it's great in direct light, and is still very readable even if 50% bright and 50% shaded.
There could be room for subjective improvement by adjusting the contrast and brightness too.
Also, Read The Fine Manual - I assumed first Optrex transflective LCD had a 5V LED capable backlight like the standard display, but it didn't (it looked good for the 15 seconds before it burned out). I used a simple potentiometer the 2nd time, but a voltage divider is a better solution.
VEMS yellow/green shop display
Black on white
White on black