You can make a very bright, high contrast display with high efficiency 7 segment LED displays and appropriate filters in front of them. I use photographic filter material that I buy in sheets (Lee filters). Often a combination of a filter of the same colour as the LED, and also a neutral density "dark" filter do the trick. It's important in sunlight and other bright light because the non-illuminated segments are otherwise visible and impact readability.
The display modules I use, all have IC's that have brightness control in software. So I can (and do) vary the brightness according to time of day (you can measure ambient light too, like phones do).