Glossy displays are beautiful, but they aren't as accurate as matte displays.
It's kind of like with music, setting all the treble / bass controls to 'zero' gives you a flat, accurate sound, but it 'sounds better' (But less correct) to amp them up a little bit, which is what a glossy display is like.
I love the look of glossy displays, but I recommend matte to most people, especially anyone doing any actual video work. If you were running a recording studio with Logic Studio, I'd probably say go glossy 🙂