I have the Boss ones BCB-30, BCB-60 and that 12 pedals PB1000 from Behringer.
The Boss BCB-60 has better patch cables and power supply, but I don't use daisy chain PS, so it doesn't matter to me.
Besides that, I think the PB1000 have almost the same quality, is bigger and cheaper.
And yes you can take that slotted sheets and replace with another, cutting the new slots the way you want for different pedal sizes, some screws will be in the way, but you could just don't use some of them.
The only thing I don't like is the weight of it fully loaded, very heavy.