In my experience, the stackers are more durable and hold more. But the inlines are much easier to load in a car, unless you're going to disassemble the stacker every time you get in or out. And that's fine until the first time you get to the center and it's raining a flood outside.
I have an Ebonite inline three-ball roller right now with the fourth ball in a zippered pouch on the outside. One of the wheels has come apart, but I managed to fix it. It had a plastic wheel covered in a rubber surround but if you leave the bag sitting loaded in one place for too long, the weight of the balls will deform the rubber (i.e., flat-spot it like a tire) and then it won't roll smoothly. I took the rubber off and the problem was solved.
I'll probably stick with the inlines in the future. My 4-ball stacker is just awkward to put into any car without a huge trunk.
Jess
