I used to have a laptop with a glossy screen, and used it outside frequently. These screens change the amount of reflection into an all-or-nothing case, rather than mostly washed out, or just slightly washed out of normal LCD's. A few tips to make it slightly less annoying:
-Don't sit with anythign brightly colored, reflective and/or sunlit behind you (Bright green grass, bright white sheets, the sun, etc
-Tilt it down, It's similar to a one-way-mirror. Reflections will angle down, but the backlight will still pass through normally.
Glossy screens aren't really better or worse at managing reflections, they just reflect it all in one direction, rather than diffusing it everywhere. I'm no scientist, so I couldn't tell you the math behind it, but all of the above has worked for me in real-world scenarios.