Task Forces give reward merits that you can use at the merit vendor to buy SO enhancements for your level at 1 reward merit each. Task Force - Unofficial Homecoming Wiki
This lists the task forces, their level, the amount of merits rewarded as well as all other relevant information for the taskforce. You can do task forces below your level and you will receive rewards (although you will play as if you were of the correct level for the TF)