Another responder mentioned block sizes.  Yes, that mb the problem.
I'm new to USB sticks & haven't formatted them in any way:
they seem to have an existing file system on them,
but mb it's Fat32, which seems likely to be inefficient.
So are there any standard recommendations for formatting them ?
Do I simply do 'mke2fs' (the HDDs are formatted with ReiserFS) ?
How about block size ?  Thanks for the replies so far.

Sticks are usually formatted w/FAT16 as M$ is giving people a hard time about FAT32 (which is even more inefficent.)