Ok things to notice with this, if you have a shiny floor, light wood / laminated flooring etc, these will not work as they are. You WILL slide across the floor and it is damn dangerous. However, there is a way around this (at an additional cost) - I went to my local carpet shop and got a rug grip, placed this down on the floor and then these mats on top. This will eliminate the sliding on the floor, ok so thats good. You can then cut the gripper and stick it to the bottom of the mats.
The mat surface is pretty good at being non-slip, it's not 100% non slip but very good, soft enough to cushion the impact of all the moves. One thing is that you have to be pretty patient when assembling if you have more than one pack, some of the joins aren't perfect so you need to move them around a bit and push them together, however with the rug grip on this is no real issue.
tl:dr - If you have a smooth floor, don't get unless you are prepared to modify.