Thermaltake Matrix VX Case
 

Which case is better, Aluminum or Steel? To answer this question properly one must first quantify what advantage(s) each material brings to the table. Steel (SECC) is stronger and generally more rigid than aluminum leading to less resonance which in most instances decreases the noise from vibration of any components inside the case. Aluminum is much lighter weight making it much easier to move from one point to another. Aluminum is also considerably easier and probably cheaper to fabricate and manufacture.