Lexar 1000x CF cards....? Do you use them? Should I buy one?

I would like to buy the Lexar Professional 1000x 16 GB cards. (initially, I wanted to get the 600x versions but they are no longer available.) I have looked at the reviews and lot of people are complaining about the fact that these new 1000x cards fail. I am a wedding photographer and can't afford to lose photos...although I always back up the pictures in the dual slot.

My question: Have you ever used the Lexar Professional 1000x 16Gb series cards and what your experience is....?

I've got 2 32GB and 2 64GB Lexar 1kx for about 5-6 mths now. They're working great and haven't failed yet. I shot 25+ frame in continuous mode without issue constantly in June/July. Dunno about the 16GB.

Is it as fast as they supposed to be? Can you feel the difference? Thanks!