I actually have Lexar thumb drive sitting here ATM (not really its actually custom dual stack hardware encrypted supporting MGM2 flash made to appear that way). Point is SanDisk has less than 1% margin of defects and they have the highest quality of build. I am sorry YOU had cards that were marginal quality, could have been that you got none legit cards created during shadow shifts, Kingston and few other folks actually buy mSD that does not meet SanDisk's QC and they in print their own logo and sell them. Don't call me SanDisk fanboy

I don't even own a single SanDisk card I know they are overpriced but for normal consumers they are good.
Example: SanDisk 32GB Class 2 vs Kingston 32GB Class 4
If you look at some of the benchmarks posted by folks even myself all over sites you can see it for yourself. I don't buy other than reputable dealers as Storage Admin I learned my lesson and now I have 28.1TB NSS. Fact is Samsung and SanDisk actually invested billions flash memory ventures, I believe they also have co-op in facility. Lexar is like off brand you get those yellow or whatever thumb drive on walmart lol for $5.