Reiserfs definitely screams relative to ext2fs on larg directory listings. Example: the IWE forums archive consists of single-file posts in one directory, with 124,657 files. Doing time \\ls | wc -l on the directory reads in just under four seconds. Read time under ext2 was significantly longer, many seconds, possibly a minute or more. Turning off directory sorting (-U flag), read is reduced to under a second (0.791, 0.772, 0.856, 0.780, in repeated trials).

The difference: reiserfs stores directories as hash tables. In ext2fs, they're serial lists. It took literally hours to unpack the archive I'd received from Craig under ext2.

Note that there are still issues with large directories, but rieserfs will deal with them.

Note also that I'm using an escaped 'ls' to disable colored listing, which requires reading the first few (512 IIRC) bytes of a file to determine its magic. With "--color=auto" and directory sorting, the listing takes 2:32.097s to run.