The new Moneual 312 case certainly is smaller than the Silverstone Grandia GD01MX, in all dimensions :
What is also manifestly obvious is build quality, the Silverstone is made out of solid material, I think the case itself is steel, fronted with aluminum. It is one heavy beast but that has some significant sound deadening qualities in its own right. What's more you can see Silverstone have put some thought into airflow and making sure air flows in a suitable path for a PC.
The Moneual is disappointing at this point - the GD01 takes a firm grip to get onto the table, the 312 could be balanced on one finger, thin aluminium everywhere, not that I would as the risk of damage to the black surfaces looks all too likely so a firm grip is also required. The top of the case fits securely and there is not messing around trying to line it up to slide into place but the sides / rear bend worryingly while getting the snug fit back in place. I am surprised in the reviews I've read that no one has seen fit to mention these details - looks count for a lot but a lasting finish is critical at this price level and those surfaces will drum badly on a higher spec machine.
Worse still is the airflow, it looks to me that Moneual make stereo equipment not PCs - there is no attempt to provide an airflow path, the case is riddled with grill like cut outs , they are well cut, look smart and have no sharp edges but I don't for one moment imagine airflow will be directed in a coordinated fashion across the surfaces that need it.
For me, with the Asus E45M1-M Pro I'm not expecting huge issues with heat generation and I already know my drives won't overheat but the bigger issue I see looming is dust, I'll be forever having to take the case off the shelf to dust the insides (with 2 adults, 1 small person and 2 cats we do generate a good amount of dust).
The reviews I've read also suggest getting a couple of 4cm fans to dissipate heat from the word go. Well I can see two 4cm mounting points but I agree with other reviewers, nasty little 4cm fans aren't very effective and often disproportionately noisy. I do, however, wonder if Moneual have responded to those reviews because one of the largest cut-out areas is directly over where any processor will reside. I would imagine if you have heat problems then the route for venting would be a standard style processor fan as supplied by Intel / AMD or something like a Scythe Shuriken (not sure of the measurements but I'm sure the low profile model would fit, likewise the BIG) where air is pulled over the heat sink & up through the fan and towards the top of the case ... and out....would be best that the machine has decent clearance above on that basis but looks like it would work nicely and make diddy 4cm fans a pointless affair.