Not the first time I've heard about quality problems with Sandisk cards recently. In Europe the warranty can be pointless as they want you to mail it in to their Czech Republic offices, at your own cost... I just got a Transcend one and it's fine so far.
General considerations for SD cards are the type of memory used (MLC, SLC, TLC) which will limit the number of write cycles. MLC is most expensive and best. The other thing to check in the data sheet is whether the card does internal ECC error correction. Apart from that the consumer warranty service may also matter
