Personally, I find the display usable in direct bright sunlight and I drive with the roof down whenever I can. It is certainly harder to read in these conditions but still possible even in the worst case. In bright sunlight, very occasionally I do have to move my head slightly (to be more ‘on axis’) rather than glance down, and I might shield the screen with my left hand if I need to see small detail in a corner. Undoubtedly, a more expensive and brighter unit would be better in these circumstances. However it doesn’t bother me and doesn’t effect usability for me given that I’ve never had to pull over or close the roof mid-journey just to see the screen.
Frankly, that worst-case i.e. low sun shining directly on the screen also doesn’t actually happen very often in practice. Even on the sunniest days, more often than not I am driving into the sun or parallel to it in such a way that the light doesn’t directly hit the screen for more than short periods and it’s only really ‘direct hits’ that make it at all difficult.
In summary, I doubt the max brightness would bother anyone unless they were particularly sensitive to it for some reason or lived somewhere and did regular journeys that meant most journeys were sunny with the sun position mostly behind them.
Reflections aren’t a problem at all. The screen is a matt finish. I never notice any reflections when driving, though logically some light must be reflected.
One other thing to mention is if you use polarised sunglasses. There is an inherent issue with backlit flat panel display technology and polarised lenses. Relative to other devices around the home the 3005 screen is actually pretty good in this regard. At certain oblique angles, the screen light can be filtered out by my glasses but in my natural driving position, it’s not. Just something to be mindful of if you like polarised lenses and are comparing different units. Very few reviews mention this and I’ve found there’s a lot of variation (e.g. my fitbit screen appears off unless held directly square on and n front of my face).
For the price I paid, I’ve been satisfied with the screen quality.