Reports are that the Pebble Time Steel, which uses the same screen tech, is much more vibrant than the Pebble Time due to the optical bonding. The PT Round looks to also use that same technique due to its thinness, so I expect it will look quite good.
Aha! I do own the Pebble Time Steel and couldn't identify with the issue of the poorly readable screen. I find it reads very well in direct sunlight, and when it's dark there's always the light button. I guess this explains the complaints.