My family has done this for years, originally with Garden of Eden and now (for the past 4 yrs) with Golden Earthworm in Jamesport. I prefer the variety of www.goldenearthworm.com
When we first did the CSA w/Garden of Eden, we felt that they kept the better produce for their farmer's markets. They do grow delicious tomatoes, but we didn't feel what we got in the box was the best of their crops. Maybe that have changed that since, but just my experience. Have been very happy with golden earthworm, am signed up for next year as well.
I wouldn't recommend a CSA unless you like to eat a lot of produce and like a good variety. Like if you don't like salad, greens, etc. or your family is picky, don't do it. We eat anything and so do my kids (mostly), so it works out very well. I mean if you don't like brussel sprouts, no big deal, but if you only like broccoli, green beans and spinach, then you're going to get a lot of kale, carrots, turnips, bok choy, etc. And then it's a waste.