FS of choice for max random iops ( Maildir )

[freebsd at top-consulting.net]

I have a new server that I would like to use as a back-end Maildir  
storage shared through NFS. The specs are:

FreeBSD 9.0 Beta 2
Xeon x3470 @ 2.93 quad-core CPU
4 GB Ram @ 1333mhz ( upgrading to 12GB tomorrow )
3WARE 9650SE-16LP card with write cache enabled ( battery is installed )
16 x WD RE3 1TB drives
RAID 10 setup

Right now I defined an entire array of 8TB ( all 16 disks ) separated  
in two pieces. 50 GB for FreeBSD to boot and the rest available to  
configure as storage.

I've tried three options for the storage file system but I'm not sure  
which one is the best option since I can't really reproduce production  
conditions. I only ran tests with dd and bonnie and here's what I found:

A. TEST1: dd bs=1024 if=/dev/zero of=/data/t1 count=1M

1. ZFS performed the worst, averaging 67MB/sec
2. UFS + gjournal did around 130MB/sec
3. UFS did around 190MB/sec

B. TEST2 ( random file creation ): bonnie++ -d /data -c 10 -s 0 -n 50 -u 0

1. UFS + gjournal performed the worst
2. ZFS performed somewhat better
3. UFS performed the best again ( about 50% better )

C. TEST3 ( sequential writing ): bonnie++ -d /data -c 10 -s 8088 -n 0 -u 0

1. UFS + gjournal crashed the box
2. ZFS performed average
3. UFS performed better than ZFS ( about 50% better )


I really like the concepts behind ZFS and UFS + Journaling but the  
performance hit is quite drastic when compared to UFS.

What I'm looking for here is max IOPS when doing random read/writes.  
Is UFS the best choice for this ? Do my results make sense ?