Fast file system for cache directory with lot's of files
 

Howdy gentooers,
I am looking for a filesystem that perfomes well for a cache directory. Here's some data on that dir:- cache for prescaled images files + metadata files- nested directory structure ( 20/2022/202231/*files* )
- about 20GB- 100.000 directories- about 2 million files
The system has 2x Intel Xon Quad-cores*(Nehalem),*16GB of RAM and two 10.000rpm hard drives running a RAID1.

Up until now I was using ext4 with noatime, but I am not happy with it's performence. Finding and deleting old files with 'find' is incredible slow, so I am looking for a filesystem that performs better. First candiate that came to mind was reiserfs, but last time I tried it, it became slower over time (fragmentation?).
Currently I am running a test with btrfs and so far I am quiet happy with it as it is much faster in my use case.
Do you guys have any other suggestions? How about JFS? I used that on my old NAS box because of it's low cpu usage. Should I give reiser4 a try, or better leave it be given Hans Reiser's current status?

Thx in advance,Mike