I have SmartPots, and they work really well. Mine are 15 gallon. I've grown tomatoes, potatoes & cabbages in them. The larger volume of soil in these hold water really, well, and, they do not dry out as fast as smaller ones - just like with other containers. I do have several small (7 gallon?) SmartPots, and they'd drive me crazy with having to water every single day. I haven't planted anything in those...
I water my large(r) SmartPots once a week, just like all my other veggies. Maybe twice a week to get a transplant established. I love being able to just dump the whole thing to harvest potatoes, or to refresh the container mix...
The fabric helps a lot with root aeration, too. To date, I've not had a plant fail in a SmartPot.
All in all, I'd recommend them for a small space or container garden.
P.S. There's a YouTube video that shows how to make your own, if you are so inclined....
