From all the reports, Trim can be enabled safely on your Mac. I have it enabled, and don't experience any issues. Of course, until Apple supports Trim on non-Apple Solid State Drives, there will always be some controversy about the practice. Use the application "Trim Enabler" available at http://groths.org, to enable this feature on Mac OS X Lion or Mountain Lion. You can verify operation by clicking "About this Mac..." in the Apple Menu, and looking under the Serial-ATA category in the System Report. Trim Support will indicate "Yes" when Trim is enabled. You can force a Trim Collection operation by rebooting your Mac while holding down the "Command" and "S" keys, which will startup in "Single-User Mode", and present a text screen with a "Root" prompt. At the prompt, type the following command, which is listed on the screen:
This will initiate a disk repair operation, much like if you selected repair from the "First Aid" tab in the Disk Utility application. Near the end of the operation, the message:
** Trimming unused blocks.
will be displayed, showing that the Trim operation has been performed. This technique forces a Trim operation, but is not required for the proper operation of Trim once it has been enabled.
Of course, it is time for the obligatory disclaimer: Use of the recommended software and above recommended operations are entirely at your own risk! That being said, the above techniques are well established, and should not cause any harm to your system. The benefits of Trim in conjunction with a drive's internal garbage collection routines have been well established and documented.