It looks like it is really lacking floor space. The only place they could walk on a flat surface for much space is all the way on the bottom, those shelves are really small. There's not much info on it that I can see either... But it is a bit smaller than a Double Critter Nation and just about the same price. I would get a Double Critter Nation instead, it's only about 30$ more.
I think it would probably fold down easier from the description. I haven't had that one, though I did have the previous model of marshall before and it was much easier to fold down than a dcn.
I wouldn't worry about floor space-I actually like that about it. Both my dcn and my quality cage have full floors which imo make it more difficult to set up for a lot of climbing, which is good exercise. Adding things to sit and play on is easier-big litter boxes, plastic bins, hammocks ect can be hung on a cage. You can use thick ropes, perches, branches and ladders for climbing.
Cons that I see-Smaller rats can probably easily fit through the bars-I'm going to say never suitable for girls or young boys is likely. Most full adult boys should not be able to get out, but you could have a little guy. My QC is a ferret cage and the bars are 1x1 squares and none of boys can get out, and I could use it for my girls..but it would be risky. This cage has bars that are slightly bigger than an inch apart and then they are not squared like mine so making it an even larger gap to potentially escape out of. Doors are not as big as a cn, yet the cage is deeper, so may be a pain to get to back corners of it to clean or decorate.
I had concerns about the doors as well, hadn't really thoigh much on spacing as it would be for the boys (who are young now, but I have a smaller "in between" sort of cage I could use for the time being)