The numbers on my Sigma computer (an older 1009) are sufficiently large, and the material they use for the LCD display is highly visible in low light. My Garmin 500, on the other hand, is hard to see in low light, of in bright sunlight but with my shadow over it. Plus, it seems like the Garmin Edge (the bike computers) engineers (who must obviously all be under 30 years of age) chose a font style for the Garmin 500 display that is extremely (and I mean extremely) difficult to make out. Will have to check out the 800/810 to see if there's any improvement.
Luis