I've been using for many years as a professional CF cards from Transcend. So far no failure. Through the years, I'm with the capacities and write speeds at which the manufacturer hardly even find new words that go beyond ultra and hyper, but it has grown to the specified data almost never make it). Transcend is now a brand that very holding back the market cries and brings it rather good and affordable cards on the market. I also have to compare 400x and 600x cards in use. My fastest camera, the EOS 1DX that exposed in series Speed Mode 14 RAW images (a ca 20MB) per second and of which 34 are in series. If I use a 400x card, the camera writes to the 34 sequential shots only once, but can already single new exposures to. In the 600x card further exposure will already liquid and in the 1000x, it almost did not increase. When exposed at the latter two at medium speed, that goes without any break ...... My conclusion, 400x is sufficient for the quiet landscape photographer, 600x is good, fast and inexpensive, for almost all applications, 1000x is super fast, and inexpensive, and the safety of the maximum write speed (quality reportage, sports and dance) offer because sometimes it precisely the special and unique moments, where it is of the essence (for which you indeed get his money) and if you have to then wait because the camera just "thinks" that's the least annoying. For video, I can say nothing, because I'm just a beginner. The read speed is secondary for me and I have to made any Bobachtungen.
The only drawback, so large card is the maturity of rescue programs, when it happened that a problem occurs, or, like me, something accidentally deletes ......
