I don't think the kind of container you use matters as much as matching the container size, potting mix and location of the container to your environment. I've used all three kinds. My favorites are 20 to 25 gallon fabric containers using 5-1-1 mix and sitting in contact with bare earth. If you don't put them in contact with the ground so they wick to the earth, you lose a lot of the benefits. Search the phrase "site: gardenweb.com smart pots" on Google to find many of the previous discussions of grow bags.

Ohiofem, don't the fabric containers dry out ridiculously fast with a 5/1/1 and ground contact?

I'm WILLING to water a lot, but I have a job, wife, kids, and a life, I can't sit in the yard holding a hose all summer!

I guess I get nervous, since even a couple of the plants I had in MG Moisture Control mix last summer were wilting in a day and a half in the hot sun.

Hairmetal: I think we talked about your problem with those plants before. I don't know why you had a problem with them. But, as I said before, I don't normally have to water any of my plants in 5-1-1 more than once every other day. This goes for six-foot tall tomatoes in 25-gallon smart pots resting on the ground as well as flowering annuals in 16-inch hanging baskets lined with coco fiber. If it rains at least an inch, they can go three or four days without more water. If you make the 5-1-1 properly and you use a container that is big enough for the root system, you will not have a problem. 5-1-1 holds a lot of water. The ground doesn't suck it all out of the pot.