The vouchers for fruits and vegetables are great. Also I know that there is a $25 vouchers for WIC participants to shop at the Farmer's Market each year in the area I live in.
There are some other good things that WIC promotes such as breastfeeding. They provide Lactation Consultants for women who chose to breastfeed. Also good grade pumps are available for women that are working (thought I think many low income woman don't work in a pump friendly environment to actually utilize these pumps). Vouches for omega- 3 riched tuna are provided for these breastfeeding mothers also. So its not all bad.