I don't know which benchmarks these were, but there are only a couple of things that ext3 does slower than ext2 and generally they are very similar in speed overall. They are essentially the same filesystem except ext3 has a journal, so there is no reason not to use ext3, esp since ext3 has the journal and recovers better from unexpected power downs and such - which I get a lot of here.
Reiser is also good even if Hans is a pain at times
I'm quite sure he want the world to be all using reiser4 in the near future
The only problem I've had with reiser is that it tends to store lots of small files as a big file, so there are times you can possibly lose more files when you lose a disk cluster... But generally these days disks go bad with a bang anyway and you lose the lot... We all agree reiser is all round the top performer at the moment, but performance isn't the only criteria for everyone.
I went back to ext3 from reiser mainly for compatibility as at the time few bootable rescue floppies had reiser support, but they did have ext2 which is enough to get files off an ext3 disk... I also just feel ext3 is a proven workhorse while reiser was going through a lot of change a couple of years ago. Once you shift you tend to stick with what works for you.