Our raised beds are also 4 x 8 feet, but accessible on all 4 sides, paver walkway in between. We add leaves and compost out of our rabbit manure pile to ours, along with some worms. Like Maggie said in another thread, nematodes can be an issue if you don't rotate crops. Some years we do all cabbage, brussel sprouts, and the like, sometimes several varieties of onions, then the next year it'll be all tomatoes, sweet and hot peppers, etc...sometimes just watermelon...grew a yellow meat Moon & Stars watermelon year before last that was 37 lbs when I picked it.

Raised beds are easier to feed, easier to keep weeded, easier to keep watered, grow bigger and better produce, and are definitely the way to go! I've seen pictures before where people even planted peas and beans in them...you'd be amazed at how densely you can plant and still make an outstanding harvest, as long as you keep your plants fed.