mikecindi, this article at Linux.com will give you a first-hand account of JFS' use:http://www.linux.com/feature/119025
Although 30 days of use is not a lot, the author did some crash testing during those 30 days and never had any problems recovering (and recovery time looks pretty good too). User comments also seem quite positive in general.
Personally, I have never had a reason to leave ReiserFS and I just love it. Though there are some chilling stories (somewhat dated ones though) of Reiser filesystems that have crashed and burned leaving the user with a corrupted filesystem (and using fsck only worsens the damage).