How durable and reusable are they? Part of the reason I grow in containers is the ability to move them around... if the larger sizes, say 5 gallons and up can't be dragged around, especially on abrasive concrete without ripping up, then they're not for me. Right now my fav containers are 10 to 20 gallon polyethylene tote/storage containers with holes added to the bottom... more years of use per dollar if you catch them on sale, but not as much work as sawing in half, 55 gallon plastic drums.
I dont think they would be durable enough for dragging around on concrete. Maybe if you had them in a drip tray. They are quite cheap though, less than $1/bag. I have a Thai Dragon and an Odham Indian in 5-gallon grow bags in my container garden outside. I used mostly Smart Pots this year but did a couple in grow bags for comparison. I think the smart pots are better, but they are also much much more $$$. Supposedly they can be reused, I wont know until the end of the season.