[sciurius]

Well, it wasn't even sunny and I still had a hard time reading the tablet under bright daylight conditions. It seems the anti-glare filter catches and distracts the light, making it look like ground glass. I checked my collegue's iPad and this one was much better to read.
So although an anti-glare filter is great under most circumstances, it's not a good idea for bright daylight conditions. It's a pity it is so hard to put on otherwise I would definitely have considered removing it just for the gig.