It's the only card I've ever used which has ever lost data. SanDisk 256MB (Bought April 2006, bundled with Casio EX-Z850) Lexar 32x 1GB (bought February 2005, $95) SanDisk Extreme III 2GB (bought September 2006, $112) Microtech 256MB (bought February 2002, $140) SanDisk 2GB Extreme III (bought February 2006, $120) SanDisk 2GB Extreme IV (borrowed September 2006 review) Photojournalist Karl Grobl, loaned me his new SanDisk Extreme IV combo, so I decided to compare it to the other cards I own. This is how long I need to wait around to get the images into my computer. I use both fast and slow cards and have never noticed any differences in shooting. Therefore I don't care about write speed in my camera. I've never been able to fill a buffer on any of my cameras, ever. It is next to impossible to overflow the buffer unless you're doing something silly like shooting numerous, continuous 15 shot bursts in uncompressed raw mode. You do not have to wait for the card, unless you overflow the buffer. The buffer writes your photos to your card while you are taking more pictures. Buffer memory stores the photos you just took before they get written to your card. Modern cameras have internal buffer memory. I don't care about it for shooting, since camera memory buffers eliminate any shot-to-shot delay even with a slow card. See also separate SanDisk Extreme IV Review and Lexar 300x UDMA Review. This prevents the possibility of data errors and corruption.
Pro Tip: Always format every card in your camera (not your computer) every time you use it. Helps me publish this site when you get yours from those links, too. Get my goodies at Ritz, Amazon and Adorama.