It's kind of a mix. You can update quickly without burning battery on changes, but it needs power to keep displaying things. On the other hand I'm not sure that's a bug on a watch; I don't want it to display the last time before its battery died indefinitely. And it does work in direct sunlight which is great

If you have not seen a transreflective color LCD in person, my suggestion would be to search for reviews of the old Pebbles to get a feel for it (or just get one, they can be had for very cheap sometimes). It's very different that the LCD in a phone - and much more readable in sunlight, for example.