I have been struggling with this decision for the past couple weeks as I am planning on making a purchase soon. Although this is certainly a matter of personal preference, here are my thoughts and observations:
Matte:
My currrent Toshiba laptop and Samsung desktop monitor are both matte. I don't use the laptop outside often, but I do use it in a variety of lighting conditions. Matte screens do get a little washed out when light is shining directly on them.
Glossy:
My intial reaction to the glossy screen was the sharpness of the screen and eye-candy factor. I also noticed the reflection of what was behind me on the screen.
Comparison:
My local Apple store had a 15" MBP in both matte and glossy right next to each other, so it was very easy to compare them side by side. There was very bright but diffused lighting on the wall directly behind me, bright and diffused lighting overhead, and bright and sharp track lighting overhead. I opened nytimes.com on both laptops, as the black text on a white background is what I deal with for most office applications. My first thought was that the reflections in the glossy screen would be distracting. When I started reading the text, however, I was surprised. As soon as I stopped focusing on the reflections and reading the text, I didn't notice the glare and the text was very sharp and easy to read. I then did the same on the matte screen. It was much like my Toshiba laptop where you cannot see details in the lighting behind you, but the bright spots did wash out the text enough to make it harder to read than the glossy.
Neither type had any significant advantage or disadvantage and any screen will have to be adjusted slightly when using in changing light conditions. I found that I did prefer the glossy in both diffuse and direct lighting, much to my surprise. So, I will be ordering a glossy MBP soon if I can convince myself that I have chance of not having the LED and keyboard issues plaguing these laptops.
