you cant really compare these 2 since they both offer different result aside from them protecting your screen from scratches..
anti-glare provides 4 functional results, prevent glares, no prints/smudges, glides easier and protects your screen from scratches.
crystal only provide 1, only to protect from scratches.
so its really up to you on how you use your phone or where you use your phone.
i personally have the anti-glare because it doesnt leave smudges/prints, its smoother than the crystal, and i can still see under the sun without me moving in weird angles to find the right spot.