I can write about this card (Transcend Extreme Speed 32GB CompactFlash (CF) memory card 400x) really only positive things. Sufficient speed - yet not a single failure. Use the map since April 2010 alternately repeatedly in my EOS 5D Mark II and Also since August in my EOS 1D Mark IV. The speed of the card is probably not soooo fast as specified but it is enough every time I use the MK IV raptor Images make in flight. Under these Bedinungen (10 fps) storing RAW images 25-30 takes max. Resolution in about 3 seconds. That's enough to my mind in any case. Failures were as mentioned in some speeches, I had not a single. For me, the TOP card and up to 3 times as expensive Sandisk is preferable with similar values. Going to buy in the next few weeks the same card again to respectively have both an Cams these cards. Otherwise I use 8GB Sandisk Extreme IV. By me for the 32GB card from Transcend the full score.
Addendum: August 17, 2011 I use 2 pcs. Of these cards. 1 pc since April 2010 in my 5D Mark II. - So far more than 20,000 shots (RAW) made absolutely 0 issues Done so far more than 10,000 shots (RAW) ... also no problem - 1 pc since April 2011 in my 1D Mark IV.
Noticing the speed of the card on the MKIV if I make recordings of prey in flight, and the Cam on "continuous fire" runs. No standstill and always immediately ready to fire.
Highly Recommended - a peak ratio (price-performance)
