I've used it and I just never took the bars off

I did any cleaning through the front door (and sometimes the top door). You don't actually need to take the top off then. When you put the bars together, the perspex section fixes to the underneath of the barred section, so if you did take the top off, the perspex would come off with it. Meaning you'd need to use the front door to remove enough bedding first anyway, otherwise the bedding would fall out when you took the top off. So I found it better to just leave the top in place and do the cleaning through the door.
@Yorkie has this cage and may be able to give more info on the cleaning side