Considered getting a higher speed card, i.e., Class 6 or 10 but my cheapness won out and I opted for this Class 4 card to be installed in an original Droid X. Despite a couple of minor hiccups involving file names longer than 40 characters the data from the old card was transferred to the new card. I replaced a Class 6 card with this Class 4 card and I cannot detect any difference in the operation or the speed. Seems to be a good marriage thus far.