I've played around with the Sortimo boxes in the store. They seem to be pretty ok to me, just as sturdy and easy in use as Festool's systainers. The only thing that I didn't like about the Sortimo were the latches. The entire Sortimo case is made out of quality plastic and then suddenly the latches that hold the lid are of very thin, very flimsy material. I got the impression that they would snap if you simply looked at them the wrong way. I understand they don't need to hold weight like the latches on a systainer, but nevertheless, I would prefer latches of a better quality.
As for the comparison one member made above between the portability of Sortimo and Festool boxes, I can't say I understand his line of reasoning very much. I rely solely on foot and bicycle to move my tools around in systainers, and they've proven to be an excellent medium to do so. Unlike you lazy s.o.b's who just stuff their trucks and vans [poke] with them I got to test their field performance to the max and they passed with high grades. The only way Festool could improve on them is to make them self propellant. Btw, I got my first T-Loc the other week, and I can say I'm not impressed. It's a step down.
