I got a U2 UFO Duality.
My main beef with duality was that I didn't get the extended version (was my fault, didn't measure it properly). My Icy Dock 4 bay SATA rack doesn't fit with so I had to saw off the upper right corner of the right side motherboard tray, this means no ATX boards for me on this PC only uATX. That is not an issue for me since this side is a Linux server/workstation. For people who got long 5.25 drive bay items, they need to be careful, at least for duality version.
The other issue is that there is no way to hide cables and route them behind the motherboard tray like modern cases. This might not be an issue when a single machine is inside the case, but my two PCs have lot of cables going for them. Basically, cable management can be a hassle.
Build quality is very good, the case is light but sturdy and roomy. I was afraid of mounting around 10 kilos worth of hard drives on the 5.25 bay, but after contacting MM they confirmed that that front panel can hold up to 18ish kilos.
Despite all this, I am very satisfied. I am not running any exotic water cooling setup, just two machines in one box so I can't comment on WC setups.