Well, most of them are built by Samsung and sold under 87 different brand names.
We use a great number of USB flash drives in our repair business. We dislike San Disc
and we like
Corsair
Kingston
Memorex,
Lexar
LG
Geil
OCZ
PNY (so far)
Crucial
We did not have good luck with
Simpletech
San Disc
Ultra
Transcend
Patriot
We find that spending the extra money for those that are protected against dropping and impact is worth it.
We use only Corsair and Kingston for our high memory devices... 8 mb to 16 mb, and have had no failures.