I've been using this card since September 2005 (9 months so far) in my Canon Powershot S2IS. I'm almost to 10,000 photos taken in all types of weather/climates, from the salty sea air at the beach to the dry air of the desert; freezing winter, light rain and heatwaves.
My honest opinion is that this is a good card and I believe the rating here is the result of a vocal minority with defective cards (defects happen in electronics). People are quick to post complaints but hardly ever success stories. Just keep this in mind when reading these reviews.