It depends on the model of Dell. On the front of the case it will tell you what it is.. Inspiron 2400, 8450, etc. Based on that I could tell you whether it would fit or not. Definitely look at better cases though. Those ones you pointed out are cheap chinese garbage with crappy power supplies.
They're the same innards, and some Japanese guy that's totally into looking like a gangster, pimping out a minivan and drawing big boobs on cartoon girls got carried away in CAD.
Go the extra $50 or whatever and buy a good one.