I am using RAID 0, with two 80 GB G2's, and of course, no TRIM. Over the past several months, my sequential write speed had dropped from about 150 MBs to 110 MBs, using both Crystal Diskmark and AS SSD Benchmark. I decided to try Perfect Disk 11 to defrag the array, with the "Consolidate Free Space" option.
Perfect Disk ran for approx 30 minutes and consolidated all free space. Crystal and AS SSD now both report 155 MBs sequential write speed. It appears that all the sequential writes that Perfect Disk did, allowed the firmware to clean up and recover the two SSD's.
I should note, that I leave about 30GB of my 160 GB unpartitioned so the firmware has room to work with.
FYI for those of you with RAID setups and reduced performance.