I have an anti-glare on my 4S (Belkin possibly..?). Had a clear on my previous iPhone. The matt is great for doing what it's supposed to do - reduce glare - and another big bonus is not having to constantly wipe the fingerprints away. This particular screen protector also has a very nice feeling to it, somewhat different to a plain clear type.
I've ordered the SGP Ultra Optics for my iPhone 5 when it arrives.
So, if you value screen visibility (not to be confused with quality) and fingerprint resistance over clarity, I recommend you give an anti-glare a try.