You will have fewer problems with pests gardening in raised garden beds. If you have had previous problems with burrowing rodents, a lining of chicken wire in the bottom of each will eliminate them. Weed control is much easier handle because you can walk around a raised bed without having to bend over to pull out, if you have any weeds at all.
Another approach is to use concrete blocks, although less aesthetically pleasing, they are inexpensive to source and easy to use. On the market are also prefab raised garden bed solutions which are made from long lasting polyethylene that is UV stabilized and food grade so it will not leach undesirable chemicals into the soil or deteriorate in the elements.
Because these beds are sitting above the ground it permits the air to circulate around the containers and allows the sun to warm them up quicker. This will allot for earlier planting and quicker germination especially in the colder climate areas.
Some of the other benefits of raised beds are: reachable - less bending and stretching gives the gardener easy access and makes maintaining and harvesting less of a task to perform; drainage - because the soil is above the ground it will not become compacted during heavy rains and will drain properly in preventing water-soaked soil;