Most high tech farmers will tell you that drip irrigation is the best possible method to water your garden.  In some ways they are right --- drip irrigation minimizes your water usage by putting the water just where your plants need it.  You don't lose water to evaporation and you don't waste water by irrigating your aisles along with your garden beds.  I have seen professional organic farmers use drip irrigation very effectively, stringing long pipes under black plastic in raised rows.

However, for our purposes, drip irrigation failed us.  Here's why:

• Drip irrigation depends on extremely clean water.  The tiniest particle of mud sucked up by our creek pump quickly clogged the holes in our irrigation system, which meant that the soil around the clogged holes got no water.  If you plan to install drip irrigation with anything except city water, you will need to install a serious filter and change it regularly.
  

• Drip irrigation requires a lot of hoses and they have to be moved every year if you practice crop rotation.  Drip hoses with holes two feet apart for watering tomatoes will do that bed no good once you replace the tomatoes with onions spaced three inches apart.

• Drip irrigation is made for row crops, not for beds.  I like to maximize space in my permanent raised beds by planting some crops --- carrots, lettuce, greens, etc. --- scattered across the entire surface.  Drip irrigation just doesn't work for this setup.

• Drip irrigation is expensive.  I'm a skinflint.  Enough said.

• To maximize the longevity of those expensive drip hoses, you need to put them under a mulch to prevent UV damage to the plastic.  Since most farmers don't have enough organic mulch to cover their entire garden, they usually end up covering the rows with that awful black plastic.  Evil, evil, evil!

All of that said, we do use drip irrigation for our perennial bush fruit.  There, we made the drip hoses ourselves out of 1 inch pipe that a friend was throwing out, drilling holes much larger than those found in storebought drip hoses.  In permanent plantings, drip irrigation does work wonders.