So far, among the thousands of images did not make a single memory failure has occurred and I also can not find any reduced capacity. (SD card lock defective sectors. A reduced capacity always refers to defective memory modules!)
Of course you can also get those things out of order when they blaspheme fall over and rolled with the office chair! With regular use but they are extremely reliable.
In normal use, the simple blue cards at a 10 to 12 mega pixel camera are fast enough aufzuzeichen JPG files. The simple blue SanDisk SDHC 4GB card creates 5MB / s write speed and can approximately 2 JPG per second record. Thus it is actually memory class 4 (min. 4 MB / s), although on the map only Class 2 (2MB / s) is printed. SanDisk understates here by a factor of 2.5! Mir heck quite be :-).
Even in my DSLR Canon 450D I'm mostly cope fine with the card, although I (about 15MB per image) photograph mainly in RAW format. This is because the 450D, like most modern DSLR, already has a fast internal buffer that can hold 6 RAW files in 2 seconds once (or 30-40 JPG), which are then written asynchronously to the slower SD card , This then takes admittedly about 20 sec. in the memory of the LED flashes to the camera. But I can also take pictures of the moment during storage process continues once again has space for a picture in the internal memory of Kameara. Since I mainly do single shots, this is not a disadvantage.
For the few times where I rows make shooting in rapid succession in RAW format, I got myself a single SanDisk Extreme III 20MB with / sec.
Who but not relentlessly pressed the shutter button in order to constantly make shots is served just as well by a simple SanDisk, at a much cheaper price compared to the Extreme III.
The most important thing is still the data security. SanDisk has never disappointed me. When I see the many bad reviews on some other party (partially there everyone has third reported a total loss of data!), I can only recommend always to buy good branded goods even if it maybe 1 or 2 euros more expensive. My vacation photos are me as far too valuable. If the price plays an important role, I'd rather save on the speed of the card. So rather simple blue SanDisk on which the data are safe, as a quick cheap card, where there is a risk that is all gone.